I've got the 320d with the 8 speed auto box. I would recommend it for the fuel economy, I'm getting 50+mpg and that's with normal/sporty driving and not using the auto stop/start.
I would say the auto would more than make up for the very slight drop in performance from the 330d. The 320d engine is great and is more than fast enough for real world driving, with plenty of mid range power.
It's a good problem to have to choose!!
F30 320d sport auto 18" alpine white