About a 2/10, apart from one or two scenes, he was absolutely awful. Every line delivered in that horrible monotone way, with no emotion, or effort. The acting in general was subpar, as everyone has said.

Sam Jackson was Sam Jackson in a robe, which is fine I suppose, but it's out of place in a Star Wars movie.

Natalie Portman was dreadful, which is surprising given she's often excellent. I still blame Lucas for this one.

Ian McDiarmid was awesome, both as the fairly subtle (for Star Wars anyway) Palpatine and the cackling Sidious (man did he look like he was having fun). The best of the lot.

Christopher Lee was given nothing to do, but he did it with dignity as always, a wasted oppurtunity though.

Ewan McGregor was commendable, his acting wasn't always terrific, and sometimes it got a bit hammy even, but he clearly put a lot of effort into "being" a young Obi-Wan, so I can't complain too much. He is capable of better, though.

Liam Neeson was good, as he usually always is, shame he had no part in the second two, he would have helped them a lot.

The really overdid the writing for Yoda, he was nearly imcomprehensible at times, Frank Oz did a servicable job, not as good as the OT, however.

I felt embarrased for James Earl Jones, he only had three lines in the trilogy, and one of them was "NNNNNOOOOOOOOOOOOO". Treat him better, Lucas.

The guy who voiced General Grevious was atrocious.

Most of the supporting characters were uninteresting, I can't think of any that stood out.