Current state of Bumblebee + 331.20 on LTS 12.04?

[Squishiest Fish]

Howdy folks,
I've had a bit of a nightmare run with my linux install due to a bad kernel update + BBswicth error, and I'm not sure if it was user error or another problem.

Has anyone on 12.04 (kernel 3.11.6) managed to get the nVidia 331.20 driver working properly with Bumblebee? If you have, any tips/pitfalls to avoid would be most appreciated.