IMHO, the Crossfire autostick is just OK. You really can't do a better job of up-shifting than the car's own ECU, and down-shifting benefit is reserved for the occasional passing lane boost.

I did have a couple hard runs with the new 370Z paddle shift, and it's darn hard NOT to use the things. Pretty sweet. Your thumbs rests so naturally on the paddles on the wheel that manual shifting seems instinctive. Habit forming.