I love getting a guy turtled up, i feel like my game starts to open up when he turtles.
Lately with less experienced guys, i like to try to pull off the Schultz front headlock (haven't had too much success with it.) or Anaconda...
but my first instinct is to spin around and get them hooks in.
That said, I NEVER turtle up. I'd rather go to my butt or back and deal with side control or mount than with having a guy take my back.