Gothic series is MUCH better than
2W (Two Worlds) series on certain things - especially on the immersion factor, story-telling + character development stuff. Gothic is also much harder and way more hardcore than the Fable series + 2W series ever dared to be, as well.
2W series just has better controls than Gothic, namely - mostly for the combat. Plus, w/ the 2W series - you can get really addicted to the crafting systems - 2W1 had it w/ the potion crafting; but especially in 2W2 w/ its additional weapon crafting + magic system. It has this Diablo-type of addiction w/ its crafting and upgrading system.
I think
Gothic 1 is the best game in that franchise, IMHO. It was so fresh, so different, so new, and seeing such excellent AI behavior - there was nothing like it when it came out. Great game. Though, final cliffhanger ending - was the right ending, but felt too abrupt for me and could've been expanded on a bit.
While I did like
Gothic 2 a lot and thought it was very good, a lot of my minor complaints from the original game were magnified times 10 here in the sequel (lack of mouse-look, performance issues galore back in the day when it was out on many PC's, over-used voice-actors for main + side characters that don't even change their voice-style per characters, cliffhanger ending in the base-game, and the list goes on).
Gothic 3 is a technical disaster - even w/ all the Community Patches. Underneath it, lies a great game. If they could even knock out all the issues, the game could be great. But, I don't think that'll ever happen - it would require an even more massive overhaul than what we already have. And that game's probably too big for its own good, anyways - as also the map + journal are bare minimum here and just not super useful; especially in a game this huge.
If you don't own
Gothic 1 + 2, you really should get them - especially if you love RPG's; and especially hardcore type of RPG's.
Onto 2W series...
I think
2W1 (Two Worlds 1) has the "this is so bad, it's good factor" - namely, I'm talking about how poor the story-telling, dialogue, and actual writing is.
2W2 (Two Worlds 2) improved on this stuff quite a bit, to say the least. Unfortunately - when
2W1 came out, while the game was jaw-dropping and gorgeous to look at - the game just flat-out ran like garbage on most PC's - thank God for Best Buy's Sale on it, where it was only ONE Penny.

As for
2W2 - it ran much better when it came out, on the technical side; and again, the game was just flat-out gorgeous to look at.