I personally have always remained independant, but I think clans can be fun. It is *very* important you like the people in the clan, as they will become your gaming family. But some clans have some wonderful people in them (or at least did when I was still in the thick of the gaming world).
Pros- Meet other gamers, play with them, develop good cameraderie with your clan, etc
Cons- Some of your freedom in who you play with is taken away
I guess that's about it.
Always in motion, the future is