The WEC is a funny promotion.
Zuffa, the parent company of the WEC & UFC, treats the WEC's lightweight through heavyweight divisions as the UFC's minor league.
The WEC has two of the top pound-for-pound fighters in the world (Faber & Torres) in two weight classes that the UFC doesn't even carry, 135 and 145.
WEC events are broadcast on Versus, the extended, extended cable network best known for airing the NLL & NHL.
The WEC has arguably the best commentary team in MMA. Mir has grown into the best color commentator in the game, and he keeps getting better.
The WEC is the most consistently entertaining brand in MMA. Their most recent event on the 3rd was no exception. It featured 4 free fights, all of which were extremely entertaining with a lot of action standing and on the ground.
The WEC's success/entertainment value comes from how incredibly well it uses its roster. The WEC seems to embrace the saying, "you don't need 2 great fighters for a great fight, you need 2 evenly matched fighters." The WEC keeps its fights balanced. You rarely get a fight where there's a heavy favorite that walks through his opponent.
The WEC's next event is on Sept 10th, I highly recommend setting your DVR's. Heck, set your DVR's now for reruns of early WEC events. You'll be glad you did.
Note: I'm not saying that any of the WEC's lightweight to heavyweight fighters couldn't compete in the UFC. Some clearly could, ex. Condit, but on the whole the WEC's lightweight to heavyweight classes aren't as talented as the UFC's.