I saw it yesterday at midnight. It was very good. It is easily better than Episodes 1 and 2 combined. Obviously, there is no happy ending in this chapter, but it connects the dots very well and fills in all the gaps between 2 and 4. It sets up Episode 4 perfectly, and it's almost impossible not to want to watch A New Hope as soon as you get back from the theatre. It is very emotional and extremely stinging in some parts. I really don't know how to describe it, but it will really affect you in a few scenes. I won't say when, but those who see it will instantly know the different times I'm refering to.
There are a few problems I have with the film which are only problems if you critique films for more than just sheer entertainment value. The dialogue was awful at times and the acting was wonderful by some actors, but painfully bad by others. There are a couple things I felt were not set up well and relied too much on the audience knowing what happens in the series rather than expand on some issues.
Overall though, it was a very good film and based on sheer entertainment value, it's a 10 out of 10.