I had a very brief look at the rules last night, and when I say brief I mean very brief. But what I saw I liked, and I'm now dying to buy the rulebook myself, although I think I'm going to have to wait until after christmas.
Things that struck me as cool in the brief overview I had of the game:
Wealth - great idea.. finally a way to get rid of all that scribble at the bottom of your character sheet counting gold.
Action Points - just the general idea of them seemed cool, then I read that they are needed to use certain talents.. very cool.
The class and profession (or whatever they call them) system - it seems incredibly "configuarable" (not the word I want, but you get what I mean). I did find that the "creative" and "celebrity" professions cross a bit but I'm sure it'll work out well. I like the idea of basic and advanced classes, and that they don't predetermine what you are as much as D&D. I also hear that there will be prestige classes in the expansion books.. so lots of room for change.
Ability to merge with traditional D&D - since the D20 Modern system is based solely on humans they have automatically included the extra feats and stuff that a human gets. If you wanted for example modern day elves then you could quite easily include them, as long as you remember to get rid of these special things the humans get.
I'll be getting involved in a game after christmas with any luck. I think it's going to be a magicless game. If it is I hope we get psionics, I quite like the idea of a modern world with psionics because it kinda makes sense (and if you believe some people, we already have one).
There's an expansion pdf on Wizard's website. It had a "degauss" spell. I love it! I'm going to find it really hard to fight the urge to play a techie when I do finally play.
Anyway, if anyone has had a better look and has more thoughts on the game, I'd be interested to hear them. When I finally have a copy and have read it cover to cover, I may have some more interesting insights.