According to Consumer Reports, you will never get the kind of exhaust from an over-the-range microwave oven with range hood that you would get from a range hood without MW oven. If you are a "serious cook" and I think you are judging from your choice of range, you really need to think about a range hood that dumps at least 300 cfm (cubic feet per minute) of exhaust to the outside. Proper exhaust is the one thing that often overlooked. You'll regret it if you don't attend to this need right. Vent-a-Hood is one option; there are many others. Broan, for instance, offers range hoods with remotely located motors (in the attic, maybe), so they're not so noisy. Look for another place to locate your MW/convection oven. BTW, do you really need such a combination oven if your range contains a convection oven?

Thanks. The logic behind the convection/microwave combo (it doesn't have to be convention per se, just a regular oven) was to have a second option for warming, etc... so we wouldn't need our countertop toaster oven anymore and could get back that countertop space.

As for the hood, if we went for an under-the-counter Vent-a-hood would it be possible to mount a microwave above that or would it be so high up as to be unuseful?

Thanks.

There a several OTR units that have 300CFM, including Velos. I'm not sure 300CFM would be enough for that range, however.