Yep, join OD and prosper. .... Wait... did OD just pimp me out?
Ok points to a good guild fit.
Size isn't everything. Yep, I just said that. A big guild can be over-whelming to the new player. Age is far more important. IF the guild has too many players that are too far advanced, and too few that are at your level or slightly above or below, then you will not profit from the big guild at all. More people to M/P you? Maybe, maybe not. So consider the age of the other members. Visit a few cities and have a look at what you are getting into.
Leadership is key. And the only way I know to have a view of that is maybe forum activity.
One thing I can say for certain is that OD runs a good, balanced, no-drama, profitable, active guild. 'Nuff said.