Any 36" oven will need roughly 30 minutes for a true preheat temperature to be achieved. Despite whatever the marketers will tell you. If you want faster preheats perhaps a 48" range with the smaller oven or a standard 30" would be better to consider.

Miele gas us a comparison recently. If my memory is any good, miele tested on 240V electrical (so Manhattan wouldn't apply) the miele range hit 350 in about 12 minutes and the wolf was around 16 minutes. I can try and find the info miele showed us from their testing. That being said, that is the time for the air in the oven. You should preheat for 10-20 minutes longer than that if you are baking or doing any complex. That extra time is to get the oven cell and racking to a consistent temperature.

I have a 30" wall oven (Miele). I regularly preheat for 30 minutes. Years ago, before I bought the oven, I was told to expect that. The dinger goes off before 30 minutes. But the oven will not be fully and evenly heated before that. With one of those bigger range ovens I would expect 30 minutes minimum no matter what anyone says.

One thing about the Miele that is not well known and that mutes the entire preheat argument. Their auto roast setting starts in a cold oven and requires no preheating. But the food is done in the same amount of time because the top and bottom elements are used and the oven algorithm compensates. I use this setting so often I would buy the oven again just to have it.

You don't need a special setting to roast without preheating... I have never preheated when roasting and that has always gotten me great results in both high and low tech ovens. Granted, I haven't really compared roasting time preheating vs. not, but I can't imagine it would make a huge difference in most cases. I'm generally not super precise about roast time anyway and prefer to use a probe most of the time (admittedly that doesn't always work as well on thinner cuts of meat).

But Austin: seriously, if you're sure you have it down to those 2, just get the Miele. Both are very well built machines with lots of great cooking modes and features. One has the potential to flake blue porcelain into your food, the other does not. Yes, I know you had a Wolf DF before with no problems, but with such an expensive purchase, do you really want to take the risk? And yes, the Wolf may bake a little more evenly, but the Miele will be pretty darn good as well, and it will throw in a bunch of goodies that will probably more than compensate for that tiny bit of evenness. Combine that with the 5 year warranty... to be honest this decision really seems like a no brainer to me.

Thank you all, I think we are set to go with the Miele!