I just got mine yesterday, it rocks.
It's longer than the original, but a little thinner. The silver finish is better too. It's got less of a cheap plastic look. Somewhere between the original RW and a silver GBA SP. It feels better in the hand too.
The mouse pad is different, better. You don't have to jam on it to move the mouse around. You just apply a little pressure and the pointer keeps moving in that direction until you release. It took a little getting used to but it's nice.
The buttons are smaller on average, and I think the placement is better. With the original I found myself moving from one end of the remote to another. It still feels that way, but it's not as bad. Oh yeah, some of the buttons (AUX, PC) have a red back light.
I guess the big new feature, aside from the mouse and the added range is the AUX and PC buttons. There are four of them (AUX1, AUX2, etc), and you can assign an application to each one. So say you assign AUX1 to Winamp. Now, if you press AUX1, the RWII sends commands directly to Winamp, regardless of whether or not it's in focus. You can have another application in focus, and you can still send commands to Winamp, even if it's in the background or the system tray, and then return to normal with the PC button.
The new receiver is a lot bigger. It's kinda this black and silver blob. It reminds me of the MX700 cradle. It looks ok I guess, but it didn't mater what the old one looked like because it was hidden behind your PC.
Finally, driver installation was a pain, but only because I didn't follow the instructions. Duh. I tried to use the latest RW driver from ATI's site, but they wouldn't work. Why? Because the instructions clearly state that you have to use the ones that came with your AIW 9600 install CD. After I did that it worked great.
All in all I'd have to say that I'm impressed. I haven't had much time with it, so can't really talk about stuff like the FM Tuner support. I'll try to get to that tonight if I have time. Maybe I'll post pictures of the base. I guess if you sent in your coupon, you should probably be getting your's soon. Enjoy.