I haven't got any other Gothics than 3, but it basically is Oblivion which you actually want to play instead of struggle to death. It still tires off eventually like Morrowind of course (little sooner obviously). So yeah, would advise to give it a run if it's cheap.
Can't say I see much similarity to Oblivion in Gothic 3.
It's a game whose only saving grace is it's huge world free to explore.
Unlike Oblivion you at least have a reason to do that as you won't run into the same level-scaled content everywhere.
Sadly everything else is poor, except perhaps combat which was completely atrocious.