As the current owner of a very early-issue GSG5 and recently a GSG522P project (see my post GSG522P + SB15), I would ask, "Can you and Do you like to work on and tinker with guns?" If not, I'd recommend staying away from it. I've had a love/hate relationship with the GSG5...did the screw upgrades myself finding those tiny little things locally at Fastenal, the firing pin fix, my own cocking handle buffer design and install, original stock mods/improvements to make it solid, much sanding and fitting of magazine parts, trigger work, and finally polishing of the bolt face which solved a LONG-frustrating FTF problem.
That said, I really like shooting it, it's VERY accurate for what it is and now (finally) very reliable with CCI Mini Mags and Blazers...Federal stuff and many hollow points just don't feed real reliably. My new 522 project so far works perfectly and also is great fun to shoot. Anyone who handles and shoots either likes then as well.
It's kinda like certain cars...have the aptitude, patience and tools to work on cars, buy an MG. Don't like any headaches and wanna just get in, turn the key and drive away everytime, buy a Toyota.
Regards, s/FART