That's a loaded one. Some folks have very stong objections while for some of us it has been a very important addition in our kitchen renos. On the aesthetic side I think it comes down to personal taste and I continue to see them in very well appointed kitchens in magazines (Spring issue of "Kitchen Makeovers" has a little feature on them).

Practically I think if your kitchen has multiple users having the microwave away from the cooktop is cetainly worth considering (however this is exact reason my now reired single Mom wanted one so all her cooking appliances were in one place). I also think it isn't always the right look in some kitchens - I just pulled one out of a friends design because it just wasn't fitting in with the retro feeling of the space (thinking about putting a small one into a cupboard). Another issue is how effective they are as hoods at 420cfm my Mom finds this one to be quite good and the vents are well located for good capture. On ease of use we put this one in at 17" above the cooktop and it has been great for her. For myself under counter installation would not be desirable at all but a microwave drawer is always a possibility.

Info:

Item:
Genius Prestige Inverter Over-the-Range Stainless Steel Microwave (NNSD297S)
Supplier:
Brault & Martineau
Manufacturer:
Panasonic
Manufacturing Region:
China
Specs:
2.0 cu. ft. microwave
up to 420 cfm 2 speed fan
combines steam, convection and microwave features
keep warm menu
sensor reheat and cook capabilities
2 hood light settings
Cost:
$549.99 - Sears Canada Price: $699.99 - suggested US retail price: NA
Warranty:
2 Year Limited
Notes:
- delivery included
- vented to the outside

OTR Micro in the almost finished kitchen:

I like the way that looks. Our's had a mircowave in the cabinet above the stove but it's way to high for me to reach and I'm thinking that if it's lower I could place it back where it was before but we need the vent. Even though we have plenty of counter top space it's all open space, that leaves only one place a mircowave on the counter and it would not look good cause it is an pass through and the back of the mircowave would show on the living room side. See picture to what I'm talking about.