Hopefully someone with more knowledge will contribute on brands/models but I can tell you that a lot of the price differences that you're seeing are due to 1) built-in vs free standing 2) silent operation vs normal compressor noise 3) dual zone that are *really dual zone.

Just like fridges, built-ins cost more than free standing because of the venting needs of running successfully for years in an enclosed environment. You mention undercounter so this might be important to you. When I was looking, I read lots and lots of reports about people putting free standing units into their cabinetry and then being unhappy with either/both performance and reliability. Maybe this has changed since I looked but I can't imagine successfully getting warranty service for a freestanding unit when the tech comes and it's obviously built in to your cabinets.

The silent operation can be important to you if you have an open floorplan or if you're serious about your wine and don't want any sediment disturbed by a compressor that causes vibrations in the racks. This decision will rule out a bunch.

If you don't know, look up your wines to find out what temps they need for storage. Sometimes units that advertise dual zone have a very narrow difference between the zones and if your wines need to be kept farther apart in temperature, then you can rule out another bunch.

Also some units have a SS door (or wood finish) with plain metal sides, again like fridges, because they're meant to go between cabs so the sides are never seen. If yours will be on the end of a run, you might want to have a finished side that looks nicer.

I did buy a unit a few years ago for another house and ended up with a single zone as our house temp was cold enough to have reds just on the counter. Mine was a compressor, free standing unit from Summit. I was very happy with it for my budget but you could definitely hear the compressor kick on and off. I put the white wines at the top (slightly warmer) and the beers on the bottom (slightly colder) which worked ok for us.

cheers

I'm in the same boat Robert Ades - looking for the same thing and so confused. Can't offer much help, but here is what I've got thus far: We have a cheap, and I mean cheap ($140) 18 bottle dual zone stand-alone (Avanit, considered cheap and 'replaceable') we purchased over a year ago (model was discontinued) as a stand-in until our reno... we did put it inside a cabinet in another room, making sure to leave 2" right, left and top, with 5" space to the back. I've tested the zones, they are accurate within 1 degree so I adjust accordingly. It's very quite and we've had no issues.

We are spending more on other items so I prefer not to spend much on a built-in wine fridge - but I'd now rather have a built-in than a stand alone in a cabinet. I hear warnings of the less expensive ($1k and under, and I don't consider $1K to be cheap or inexpensive by any standards) built-ins not lasting, but having good experience thus far with an uber-cheap standalone, I may bite the bullet and go with something more affordable. I also don't consider appliances to be trouble-free anymore, with perhaps some exceptions. Reviews for 'reasonable' wine fridges seem all over the place, from horrible to great. Am currently looking at Summit, GE, and Danby.

I wish you luck in finding something you like!