I went from a Rev. B 1.86 SSD. HUGE upgrade.
x2. I just got it yesterday and have only had the chance to run Migration Assistant and get started with some other installations, but so far I really like the new screen (9CDF display). It is a big improvement over the Rev B 1.86GHz SSD model. The colors are a lot deeper.
Also, the computer itself seems a bit better built. There is no play in the screen at all right now. I'm guessing it will loosen a bit over time, but there is about 1/3" of free play on my Rev B, even after I had it tightened at the Apple Store about 6 months ago.
I do miss the backlit keyboard, though. I woke up early and checked the Migration Assistant status. It was nice having the backlit keyboard on the Rev B. It also gives it a "classier" look. Another thing I might miss is the rounded edge design of the Rev B. It feels a little more elegant than the hard-edge "wedge" of the new model. However, for me, getting 4GB and a 256GB SSD are worth the tradeoffs.