I went from what you have (still use it upstairs in bedroom) and I agree with you about the motion judder.
I upgraded to the Panasonic DMP-BDT500.
This is a brilliant player - the best I have seen for motion judder - theirs nigh on none and the picture quality is so much more detailed too than your/our Sony.
It does have it's downsides too but not much - no sacd, networking the thing is impossible for a simpleton like me (although it can be done) - far too complicated, the remote is a pain.
If its just pure picture quality that you are after then it's a great player for not alot of money if you look around.
Of course, if you are used to a Sony and like them (their menu systems are probably the best), then theirs always the new S790 which is a belter too.