I bought a GSG AK47 22 about a month ago. I originally was going to buy the S&W or the SIG522, with the SIG522 being my first choice. I decided to wait on the S&W until I am sure that new production units have the OOB fixes incorporated in them. I would have bought a SIG, but the only one that the gunshop had would have needed to be sent back for a new barrel to fix the canted gas block issue. One of the clerk showed me the GSG AK, and for some unknown reason it felt right to me. Long story short, I bought it without knowing anything about the manufacturer or without having read any reports. I've looked mine over real good, and I have not found anything wrong with it. The reviews that I found later were uniformly positive, plus I have yet to find any negative report from someone who owns one of these. That doesn't mean that someone didn't have problems, I just could not find any.
I was concerned that service and parts would be a problem, but that's not the case. If you take a look on the AK47 forum, under armory and then GSG, you will find the gunsmiths contact, and the customer service contact. I hope I never need them, but they are available.
I assume that you have actually the gun you are going to buy? If not, there's a few things you might keep in mind before you buy. First, I wouldn't but the GSG over the SIG. I do think that the SIG is the best buy. Unless you are buying the plastic stock model of the GSG, you won't have a sling mount on the stock. For some reason the wood stock models do not have a sling mount or a butt plate installed. The sling problem is easily fixed by installing a sling stud, which I have done. The butt plate will be a bit more involved, but I am going to fit one at some point. The front sling attachment point looks to me like it might be too weak, so I installed a 3 surface rail mount and use a rail mounted sling mount.
Another problem for some is that the rifle is very heavy for a 22, it weighs 9 and 1/2 pounds in the wood stock version. That's pretty heavy.
Magazines are easily found, I bought my extra one from Midway. I wish they made a short 10 round mag, but they just modify a 25 rounder to get a reduced capacity mag. This is my biggest gripe, and it isn't unique to GSG, however over on the S&W forum some guys have cut their mags down with great success. I intend to try this with one of mine. I just don't like all that magazine hanging down, makes it tough to bench rest.
The last issue I know of is that the rear sight doesn't have any windage adjustment. For the life of me I do not know why they did this. However, with my rifle the windage is dead on, so it isn't really an issue with me, but you might want to keep this in mind if you intend to use just the iron sights.
To sum it all up...I am happy with mine, I would buy it again. However, when I find a SIG522 without the gas block issue I will buy one. But, for the $364 I paid for my GSG I think it was a good buy for me. If you do buy it, please let me know how yours shoots and what ammo works best. If you have any other questions let me know. For what it's worth, I think that you'll be happy with the purchase.