From a Spurs fan, for what it's worth:
Bale often annoys the hell out of me, because he can often goes quiet when we need him most, and is always trying things that he can't quite yet pull off, which ends up leading to nothing. What he does bring however, is a player that can capitalise on the opposition in seconds. It's very easy to say that he just has pace to his game, but that is a very effective attribute to have. He's also a real threat from set-pieces and has a monster of a shot behind him when he wants. His build is very similar to Ronaldo's, though he is very far from his standard yet.
It must not be ignored that Bale has time on his side, and his attitude towards the game is top notch. He is always looking to try to improve his game, and he seemingly works very hard to do it.
I've no doubt he will leave us one day, and while he is currently overhyped in his valuation, he still has the potential to improve and meet that valuation himself. He is starting to single-handedly win us games, from a position (free roam/central) where he was so ineffective from last season. Every year he improves upon his game, and while he may never get to Ronaldo's standards, it is easy to understand why he is one of Europe's hot properties at the moment.
With all of that being said, I don't think he would ever fit Barca's system. The position he could have been most efficient from would have been LB, but his development has taken him so far away from that position now. I've no idea what the ins and outs of our partnership with RM is, but the general opinion of a lot of Spurs fans is that he will end up there. It is far easier to see him fitting in to their side than it is Barca's.