The ER2 is an awesome little pump for the money, more refined than the Talon, and most enjoyable when everyone in a group is all shooting them. I've got two.
If you're looking at running with more "serious" pump play, bumping up to the Trracer is well worth the jump. Is the ER2 on par with a Chipley, Carter, Phantom, or Trracer? Not even close. But they're still a blast in the right environment.