My GB experiences have been positive as well. I've purchased a couple guns through them and sold some stuff. No problems at all.
BTW, if you find something you like, but the pics aren't clear enough, contact the seller and ask for new pics or better descriptions. I won a nice K22 this year because some lint on the front strap looked like finish damage. I emailed the seller to ask about it and he said it was lint from his cleaning cloth. Nobody else bid and I got it for the opening price. Sure enough, there was no finish damage. The Gun is a great shooter and was nearly $100 less than similar examples elsewhere. It even has the original grips (numbered to the frame).
Chris