I own a GS graduate, and used to own a GS 2. Also have played a few in shops.
My experience has been mixed. The GS2 I bought (new from a shop) was faulty and had to be returned. It had a crack at the body/neck joint and really should not have been allowed out of the factory (or shop - depending on when exactly the crack surfaced). Also played another GS2 in a shop which had appalling fretwork. Really all over the place, you could easily visibly see some frets higher than others - again should have never left the factory in that state.
However, the GS graduate I now own (bought 2nd hand) is a superb guitar - excellently put together in every way. In fact, the nicest playing guitar I've ever played.
I have also played another couple, owned privately by friends who have been superb.
They certainly have been a mixed bag in my experience.
My theory (and it is just a theory, I have no real evidence) is that the very best guitars they make, are made from direct orders to the factory. Maybe the shop dealers get the slight 2nd's. Maybe it is that quality control has slipped a little bit in the last couple of years. Not sure.
WHat I am sure of is that it is well worth seeking out a good one.