Still having good luck with my Asena, but these are looking like a one time import, so not really available.
The big thing to watch for is mag compatibility. Most use the standard Turkish mags you can get anywhere, there are a couple that use non-standard mags, or modified mags, that are harder to come by and more expensive.
As for the price differences:
A lot of it has to do with how they were imported. Some are being bough factory direct by the importer, some are going through numerous middlemen, which drives up cost. All of them have had varying quality reviews, and a break in period needed to run light target loads reliably. The biggest pain point in general, though, has been the mags themselves. Most of the feed and cycling issues seem to be related to the mags, so it takes a while to get them tweaked to the point they feed properly (spring tension adjustment, adjusting the feed lips, etc.).
I would hazard that if you are unwilling to put a bit of time into break in and adjustments, then you might want to avoid them all. If you don't mind a bit of fiddling and break in, then you'll be happy with any of them.