I have had the Kitchen Aid KEMS308S for 5 years. I had not noticed that the microwave power was low. I doubt that power will be an issue. I assume that many ovens have cool down features. They are not running when the door is open. It is ture that the fan makes some noise, but it isn't that noticable. When I originally purchased this oven I had been intending to get individual ovens, but it turned out that the individual ovens had been discontinued. I see no difference between your choices because they are all double ovens and when one fails, they both fail wheras individual ovens could be replaced individually. I have not heard of the microwave section showing a high rate of failure. You didn't even mention the advantage of the micro/convection. It is not just a microwave, but a real convection oven with a broiling (sort of) element. It is not a speed oven because it does not microwave and heat at the same time. Actually it CAN microwave and crisp via the broil element. Anyway it is a small second oven that can bake a pie or bread (or a small trey of cookies I suppose). It heats far faster than the regular large convection oven because it is small. I find it very useful. The only problem is it is occasionally in use when I would want to reheat a cup of coffee etc. I keep an old microwave in the garage for those cases. While I hope I have relieved your concerns, I believe that there IS an issue. I have had no problem with my oven, and it has been several years since the Main contingent of problems: similar models have encountered a higher than normal thermal fuse blowing during the large oven self cleaning cycle. Unfortunately, the fuse is located on the back of the oven and is a $50 item and shuts everything down. Of course, most people see no problem (myself included) and the problem is certainly due to excessive heat behind the cabinet that could probably relieved by making sure that there is a little more open space back there since you are still installing cabinets? In any case, this is probably a general issue. Other ovens have failed on self clean cycles. At this point, many people concider the self clean to be a marketing ploy and don't use it. Perhaps we just don't make enough spattering roasts, but I have easily wiped down the main oven. It wasn't stuck on hard. Perhaps the surface has anti stick coating? My self cleans have been done mainly to test the thermal fuse problem. By the way, the microwave interior is stainless steel and IS much harder to clean. In fact, that last sentence is probably my most important piece of information. I imagine it would apply to other convection microwaves.

I replaced an old Tappan 27" double wall oven three years ago with a 30" Kitchen Aid combo unit (model KEMS308). I cut out the excess vertical framework, moved the bottom cabinet rail to adjust for the difference in height and installed a new plywood floor inside the cabinet to seat the new oven. I also had a local cabinet maker build a matching drawer that I was able to install below the ovens due to the lesser height of the Kitchen Aid vs the Tappan. I am pleased with the oven choice. Both the microwave and the standard oven have convection modes and the self cleaning oven feature has worked great.

My worry is that if one component breaks, we have to replace the whole thing Why would you have to replace the whole thing? I guess we live in such a throwaway society at this point nobody considers repairing things anymore. However, one component failing earlier is a risk to take into consideration. I went with a KitchenAid convection microwave/wall oven combo and it's worked fine for 8 years, so I can't say I regret the decision. Speed ovens seem finicky to me, and I'm not sure we really need it There are no true speed oven/wall oven combo units. That KitchenAid does not have a speed oven on top, it's just a convection microwave. The closest you'll get is the GE Profile Advantium/wall oven combo, and I'm not a fan of that because the Advantium part is only 120V, which takes longer and gives lesser quality results than the 240V Advantium. I think the best option for you is to get a speed oven or a steam oven with a separate single oven below. That way if one component fails you don't have to replace both. You will need to redo the electrical though.

I agree with Jpmom that you don't want a MW on top of a double oven - it's just too high. However, although she does not like a MW drawer, many people on this forum adore theirs (note that all MW drawers are made by Sharp, so if you decide to get one, no need to pay up for a different brand name, as it is just a rebadge). Is there no other location in your kitchen? Do you have a pantry where you could keep the MW? There was just a recent thread on this MW placement topic. http://ths.gardenweb.com/discussions/3833699/placement-of-a-microwave?n=42 I am not a fan of the oven/microwave combos, as I think there are too many compromises in both in order to combine them. Just MHO. If you are doing a major kitchen remodel, you might want to re-think the cooktop in the island, mostly because how are you going to exhaust it. This topic has been covered a zillion times on this forum, but the upshot is if you care about good exhaust, you should have your cooktop on a wall, so that the exhaust capabilities are not hampered by trying to exhaust over an island setup. On the other hand, many people are absolutely fine with poor or no exhaust, and perhaps that is you, so never mind.