If you go to the Appliances forum you will find lots of information on the Advantium as well as other speed cook models from Miele and Electrolux. Whether you will like one of these rather than a regular double depends on how you cook. I am getting a Miele chef speed oven as a second oven and microwave to go with a gas range. Getting the microwave off the counter is major for me. But we don't entertain large crowds.

I have a GE Monogram 48" dual fuel range with the 2 ovens, 4 gas burners, grill, and griddle.
I also have the GE Monogram Advantium.
I am not all that impressed with the Advantium. In my opininion, it is a glorified pizza cooker.
I would forgo the Advantium completely if I were you and just get an inexpensive microwave and have it built into your island or have a shelf built for it.

One of the things that make the Advantium a pain in the neck is that it requires different baking pans to be used for the different cycles.
These pans are large so you will need a drawer or storage area right by the Advantium.
Also the speedcook doesn't cook that much faster than a conventional oven. For example, if you want to cook a frozen 12' pizza the cycle you choose times it at 15 minutes 30 seconds. It will beep before that so you can check for doneness. It takes about 13-14 minutes. That is how long it takes in a conventional oven.
I went out a purchased a cheap counter microwave from Target because I don't like the hassle of switching the pans out and my kids use the Advantium for baking pizzas.
I watched the dvd that came with the Advantium and baked my chicken in there. I would have rather had it bake longer in my conventional oven because it browns niceley and tastes better.
These are expensive ovens and I let myself get talked into it by a rep for company in which we sell their products so it was probably self-serving on his part as he made a nice commision off of me.
My suggestion to you is to do a lot of research before buying this oven. This is only my opinion about a product I purchased and I know lots of people love their Advantiums so do what is right for you.
I will check back to see if you have anymore questions.
I love the range, but I have to cook everything in the smaller oven at lower temps than the recipe calls for or it burns.
For example, my family loves Pillsbury cherry turnovers. The box states to cook at 400 for 9-12 minutes. I cook them at 350 for 9 minutes and they are done. My larger oven seems right on.

I don't have an Advantium so I cannot comment on how well it cooks...I'll focus on it's general function...as a second oven and a MW.
How often do you use a MW?
How often do you use a second oven?
Do you use both the MW and the second oven at the same time?

If you get an Advantium as both your MW and your second oven, then realize that if you are using it as a second oven you no longer have a MW. The reverse is also true...if you're using the Advantium as a MW, you no longer have a second oven.

If you never or very rarely need a second oven and MW at the same time, then it might work for you.

In my case, it would not. I would have to have a second MW...which is sort of what I have. I have the GE (Profile) Trivection double ovens (now only available in GE Monogram). The Trivection (top oven) works as a speedcook (speed bake/speed roast/speed broil), convection (convection bake-single rack/convection bake-multiple racks/convection roast), and thermal/conventional oven (bake/roast/broil high/broil low). [Things definitely cook faster in the convection mode (faster than thermal) and even faster in the speedcook mode (fastest).]

The bottom oven is a convection oven (same as above w/o the speed bake/speed roast/speed broil).

Both ovens also work as a warmer to warm things up and as a "warming drawer" with a "keep warm" function (different functions). They also both have "proof" and "defrost" modes and have a "Sabbath" setting.

In addition to the double ovens, I have a Sharp MW Drawer.

If you're like me and use your MW frequently, then I recommend taking MichelleMarie's advice and getting the double ovens and building a shelf somewhere for the MW.

If you like the idea of speedcooking, then look into the GE Monogram Trivection double ovens.

Oh, and check, I think the Advantium does need its own dedicated circuit...just like a "regular" oven or range. I'm not positive, so check either the literature or ask on the Appliances Forum.

You can go online and get the install manual for the Monogram Advantium, but it seems my electrician had to
do something special for the oven.
There is another issue I hope you consider when making your decision and I didn't get it in my lengthy post.
The oven is big. The door is big. And the door opens down like an oven door. The advantium needs to be installed at least 36 3/4" above the floor. I would not install it much higher than that or it will be a pain to use. I never use mine as a microwave as I tend to use my microwave to heat up stuff like a cup of coffee or melt butter. It is too awkward to use. I much prefer my $50.00 Target microwave.

Yes, I'm pretty sure the Advantium needs its own circuit, though when you're twinning with a matching oven there might be some leeway on it and the cabinetry fitting. Do check the installation instructions.

Unlike Michellemarie, I'm pleased with my Advantium. When I first heard about it, in the Appliances forum, there were many people who were thrilled with theirs. Since then, a lot more speed ovens have come on the market. At the time, Miele had one, and Turbochef did. I don't know how they all stack up against each other. Back then, Miele was considered better for baking and Advantium better for microwaving.

Yes, the trays are big and awkward, and I did follow the advice to have a dedicated drawer for them, which makes it a lot easier. They sell an accessory drawer, but it is just the size of the trays. I don't think it even fits the rack. My cabinet maker made mine. The drawer sits at counter height and the Advantium sits on that, so it's a perfect height for us. The drop down door shouldn't be put too high, so it does limit the height of your main oven. I don't know about you, but I don't like my oven too low. If you have to have a spacer between the units, it might save space to put the accessory drawer there.

I haven't used the speed oven function a lot, much to my shame. I've mostly had plenty of time for slow cookery since the kitchen was done, and haven't shifted my thoughts from cutting prep to cutting cook speed when I'm pressed for time. The things I've used it for came out okay and speedy, but nothing to rival slow's quality. That may be entirely from still being at the bottom of the learning curve.

As a microwave, the Advantium is the best I've ever had. It's very even, and the sensor programs are very accurate.

As a third oven, the Advantium is everything I was looking for. Since I don't use a microwave while cooking, the losing the microwave part isn't a problem for me. It is very spacious, and will fit my supersize pyrex baking dish on the rack. I've never used it for pizza, but my 16" pizza pan that I use for lots of other things fits on the tray. It only barely fits in my big oven!

Check the Appliances forum. There are people there who have done much ovenier things with it.

It depends on what you want your second oven for. If you need it in oven mode mostly for parts of dinner that don't fit in the main oven, it's great. Equally, for speed ovening your main dish, and putting the sides in the big oven. If you do a lot of baking, and want to make dozens of cookies all at once, it isn't doing to do it.

I've just started using the kitchen in my new mountain home. I have the TOL Maytag Gemini propane range with small oven on top and larger convection oven at the bottom. Just to the right of the range (drawer bank and small countertop between) is my new Advantium 120. We were on a very tight budget and I'm really thrilled with my new appliances. I love having three ovens, I will never run short of ovens again on holidays. I'm no gourmet cook, but I wanted a really functional kitchen that multiple helpers could work in.

I haven't used the Advantium for anything other than the microwave functions so far, but it's superb at that. Yes, there are multiple trays, but my cabinetmaker made a drawer under the oven opening and all the trays and the instruction book fit in there, plus a few other items. I keep the taller rack in the cabinet below the drawer. I also kept the colored labels for each tray, to keep DH from getting confused.

I really like the way the oven door opens (down rather than to the side like most microwaves). You should check the instructions PDFs on the GE website for information on the electric circuit you will need. I wouldn't even consider a countertop (freestanding) microwave in my kitchen. I'm very happy with the look and functionality of the Advantium.

We have a single Wolf oven, with the Advantium above it. I really, really like the Advantium, although I don't know that it substitutes for a second oven. It's just a different appliance. As far as the speed referred to for pizza, etc., I agree that sometimes the cooking time isn't reduced drastically, but there is no preheating involved, and that by itself reduces the time by a lot. I find it incredibly convenient for quick meals, and with the browning capabilities, it's so much better than a microwave for those quick meals. I do, however, miss having a second oven during the holidays, or when I'm doing a lot of baking. As others have said, it really depends on how you use your appliances.

Forgot to mention that I store my trays with my cookie sheets, in a cabinet above the ovens, in vertical dividers. It's not inconvenient at all.

I have just remodeled a kitchen and like you wanted soem flexibility of a double oven but I didn;t want the microwave on the countertop. I found a solution with the GE advantium over over top of the GE single/double oven which has two ovens in the space of a sigle size. I guess it depends how much you cook in the double ovens and what you cook, but this will give me three options for cooking at once. The advantium oven also has a drawer for special storage of the different cooking bottoms and I got my husband to install that drawer in the toe kick of the oven cabinet. While my kitchen is not yet functioning, I think this will work well and not be too inconvenient - most of the time I plan to use the Advantium as a microwave so will have the glass bottom in it as the default.

mtmkp can you please tell me are the GE Advantium and GE single-double ovens the only ovens in your kitchen? I am tempted to do this set up because I find I need smaller ovens than one or two large ovens. Since your kitchen is probably up and running now, can you tell me how this set up is working out for you?

Thanks so very much!!!!