I got Gothic I when it was on sale for 4.99 USD around Christmas. I played it for about 5 hours and was totally immersed, so I went overboard and bought them all.
It is a tough game, but you really feel like you are there in that atmosphere. There is quite a learning curve...prepare to die a number of times, and save often!
It is old school rpg...it has more in common with the older Elder Scrolls games (like DaggerFall and Morrowind) than any of the newer games (Oblivion esp., and Skyrim). If you like those kind of games and you are looking for a challenge--get it.
BTW, I have been playing Gothic I in Wine on my 2009 MBA without a hitch, *after* I followed some special instructions on the Wine site. I have also installed it on my Asus G73 i7 with Win7 Ultimate, and it plays without a hitch. It does have some choppy areas in places, but it definitely is playable.
Wait, I didn't get Gothic 3 Forsaken Gods, because it got trashy reviews. Apparently one publisher or another got the rights and gave it to a hack studio to develop, to milk more profits.