I've been playing around with the Windows 7 beta; so far, can't say anything bad about it.
I'm coming off of Vista, so the first thing I can say is yes, it is faster. It starts and shuts down faster. I run Microsoft office 2007, and there is a noticeably faster startup for Word and Excel, and alt-tabbing between programs is crisper, too.
Drivers for my video card and TV tuner were pre-installed for me (nice). My anti-virus software, which was Vista compatible, would not work with Windows 7, so I downloaded one of the recommended programs.
All of my games (so far!) are working fine. The only program I've had issues with so far is the Trend-Micro.
The install procedure was pretty much identical to Vista's, and the gui interface has a very Vista feel to it.
EDIT: I've been running the Windows 7 beta for about a week now. Only a few minor issues so far: windows exporer 8 has intermittent lag and occasionally freezes (i installed firefox and it works perfect), the latest version of ventrillo would not install, but the previous version works fine.
Things I like so far: open windows management: if you have multiple open windows, and want to arrange them, you click in the title bar, drag the window to an upper corner, and it's automatically arranged in split screen for you. It sounds trivial but works very well.
The device management screen has been changed a little: now all of your devices are grouped under the Devices and Printers control panel. When I plugged in my mp3 player (sansa fuze), it displayed the following:
it was nice to see the battery life, have the options for reading the user's manual, or update the firmware.