Since 24" wide model could not fit my 21" space, I got this 15" built-in unit. It's great, with one caveat: Kalamera measures capacity using tiny 11.8" tall by 2.75" diameter bottles. Hardly any standard bottles fit that size. Normally, bottles are 12" tall by 3-3.2" diameter, and that makes a difference. Fortunately, shelf spacing is almost 3.25" (or 5.87" for the bottom shelf, but that one is depth limited to 12" because of the compressor, so it doesn't fit 13" tall Riesling bottles). In other words, standard 3-3.2" diameter bottles fit, even 13" tall, just barely, but not in the 5/shelf configuration. While shelf spacing is OK, cabinet is a bit too narrow for 5 bottles, so the best I could do with standard bottles is 4/shelf. Shelves are made of thin wood but seem sturdy enough.
This cooler is very quiet in operation, particularly when it's built-in. It eventually reaches the set temperature in the center, although spots next to the door can be 5°F warmer. I'm mostly interested in keeping wine at 55°F storage temperature, so single zone is OK (serving temperature is a separate objective, achieved by 15 minutes in the fridge or on the counter).
Finally, this comes well packaged, with about 1.5" of Styrofoam on all sides and 2" on top and bottom, which are further protected by plasticized cardboard. While there were scuff marks on the box, no internal damage! Well done.
In summary, a very good wine cooler (so far). Taking off one star for rating capacity by smaller-than-typical wine bottles. I haven't been able to find any wine (white or red) in bottles that small. This might fit ~24 typical bottles but not 30. Sufficient for me, but be aware. See photos.