I have never had the hardcore raider mindset, so I always went with more casual guilds. It has always worked out for me, there is very little drama and what little there is I can usually avoid and ignore. When I started playing WoW some friends and I formed our own guild and we just invite RL friends/family and any friends we make in-game who play as casually as we do. The guild has gotten pretty large and we have a pretty good time. We've only ever removed two or three people for trying to cause drama, and those removals were early and quick.

If you are going to raid, you will wind up dealing with some of the headaches that come with it, it's hard to avoid them. Considering that you are taking ~30 competitive people to do something that is pretty frustrating for a shot at a reward that you'll replace in a couple of months, it's pretty impressive that any guilds manage to progress at all. But I can afford to see the glass as half full, since I am nice and happy in my casual guild.