We are very happy with our ModernAire Hood. We have a 48" wide 27" deep 1200 CFM PS15-30. We went with ModernAire mostly for the styling. We wanted something with a little color and curves. They were great to work with and let us tweek the dimentions a little to fit better (I think ours is 28" high). We've been using it for about 6 months now and are happy. It is not exactly whisper quiet, especially on high, but you can carry on normal conversations. I usually put it on low if I'm cooking anything that generates any smoke at all. Only used high (or something above low on the dial) a few times when grilling or burning something in the wok. It is pretty easy to take the baffles out and put them in the dishwasher for cleaning. I don't know anything about the Viking. Our old kitchen had a Broan with worn out bushings that you could hear a mile away. Sorry about the photo being a little out of focus. I really should take some better pictures. We also have not yet finished our backsplash tile.

With conventional hood systems, the expectation is that the larger particles within the entire grease particle spectrum are collected by the baffles, and the smaller particles are ejected into the outside air, with only modest condensation or impact collection by the duct. To deal with the entire particle spectrum with a filter pack is a challenge, and probably unaffordable in cost for most residential users. If the Amazon rating is based on comparison to outside venting, the result above might be reasonable. As a commercial example, the Wells WVU-31CT filter system is described below: "Filtration Completely self-contained filtration process reduces emissions below that allowed in NFPA 96 and ANSI UL710B using the EPA 202 test method and includes stainless steel grease baffle filter with grease cup, fiberglass pre-filters, high-efficiency (Particulate Air) filter/ carbon-charcoal filter pack. All filters are easily removable with out tools. Air flow sensors continually monitor air flow optimizing performance and grease removal while an interlock system will not allow cooking appliances to function if filters are missing, clogged or in the event of a fire." About $18k. Electric surfaces only.

We're going through this right now (building our own hood) and I think you're right except that the "metal hood inside my wood cabinet hood" IS the liner. So in short you either need an all-in-one unit (the classic metal kind that hangs there between cabinets), or if you're building it in, you need 2 parts: 1. The blower itself, also called the insert or ventilator. This can be an external unit (installed on the other end of the duct from your kitchen so it's nice and quiet): or an internal unit (hanging right there over the stove): 2. A metal liner for the blower to protect the cabinet wood and ensure a code-appropriate install (fire protection). If you have an external blower, you need this to be a liner that has filters and bulbs on it to trap the grease, provide light, etc: If you have an internal blower, the liner is basically just a strip of metal that surrounds the blower insert: Clear as mud? I know, it's totally confusing - hang tight!

As someone who currently has an OTR and *IS* 5+ years down the road from when we put it in with small kids that didn't use it at the time, I can say that it WILL become an issue when they're older. My son is now 10 and he does use it and it's a huge pain in the rear. Not only is he perfectly capable of using it but he has to lift anything WAY up and over the stove to put it in and then reach UP to push the buttons. I'm always nervous he'll spill whatever he's heating and then I'll have a huge mess on the stove. And if I'm cooking on the stove, he's not allowed to use it at all, which makes him feel "little". My six year old has no issues yet. But if the microwave was lower, I guarantee, she'd be perfectly able to heat some things by herself now, which would be very convenient for me! LOL! The door gets in the way if one of us is cooking and the other needs to access it. The venting is nonexistent. I hate hate hate that we can still smell a hearty meal in the house the next day. I'd NEVER put one in another kitchen unless I absolutely had to. IMO, your kitchen has plenty of room to have the microwave elsewhere, so that's my vote. In our build, we're putting a microwave drawer in our island. It's more convenient for everyone and out of the main view as well.