The Tamashi 3P0's articulation is very good. I think (don't know for sure) it has the same articulation as the actual costume. A lot of people don't like the fact that they can't have him in a sitting position. But I don't think the costume could "sit" either. I know they made a tilt table for Mr. Daniels, so he could rest between shots. & of the few times in the movies 3P0 actually does sit, I think Mr. Daniels wore shiny gold shorts.
I'm excited for the SS one, because he'll be dirtied up, & his fingers will be individually articulated (the Tama's are not).
All that said, I originally didn't want to get the Tamashi 3P0. However, after looking at all the photos & reading the reviews on here by everyone who got it & loved it... I had to get it. & I'm not sorry. Was it expensive? Oh yeah! Was it worth it? Hell yeah! & doing the eye mod makes it just about perfect.