To keep it short, it's great.
To keep it a little longer, this is probably the best photoshop in years (obvious, right?). The interface is completely redesigned and is a pleasure to look at. It makes previous versions seem so archaic. There's this fit and finish on it that is almost hard to describe. Maybe they've taken a hint from Apple?
After fussing around with the new Content-Aware tools, all I have to say is this: Prepare to never believe any photograph you see ever again. Once these tools get finalized and into the hands of professionals, they're going to be a force to be reckoned with.
I made a few silly edits to some stock photos I have laying around, like moving windows up and down, changing where clouds are, etc. Everything is just so much easier. Where you'd have to remove an item before, re-scale it, move it to where you wanted it, then patch up the hole it left behind, now you can just use the "Content-Aware Move" tool and click and drag whatever you feel like to wherever you feel like. It's going to make what used to be serious edits quick and easy work.
Aside from that, everything else just seems a little tighter. A little more finished. I took this photo of a cowboy and ended up with an edit I'm really happy with in just minutes! It's remarkably quick and smooth. Zooming is no longer clunky and choppy, and the new darker interface is just great (as I said before).
Here's the cowboy:
Okay, sure. I could have made the same thing in CS5. But the experience was just so enjoyable in this new beta. All the pop out windows for lighting effects, filter gallery, etc have all been redesigned and just match so perfectly. This photo also employs the new Iris Blur feature. Where you'd previously have to select the area then blur it, now opens up an all new interface where you can click and drag around the shape where you'd like focus to begin. Within that there's another ring for the threshold, and within that there's an intensity wheel. It's really simple to use and yeilds great results.
If you're up in the air about it, land. It's great.