I said it before somewhere, if you didn't like 3.0, you won't like 3.1. Nothing has really changed in the game, grenades are better, which is nice, and skulks are a little easier to use. But the strengths and weaknesses of the two teams are virtually identical to the last version.
The shotgun feels almost exactly the same as the old one if you used the special crosshairs, if anything it snipes a little better.