I downloaded and installed Vista RC2 a couple of days ago. First impressions below.

Things I really like about Vista

• GUI Refresh/Update - looks really nice (esp. alpha blending tricks)
• Sidebar
• Start menu is vastly superior (Apple spotlight-style)
• BitLocker hard drive encryption (haven't gotten it to work yet, but it will be cool when I do)
• Windows-Tab functionality (cycles through open windows graphically)
• ReadyBoost technology (uses flash drives to augment system RAM)
• Built-in disk defrag is much better, no longer need separate program (sorry Diskeepeer!)

Things I don't like

• Way too many "do you want to allow this" prompts (installing a simple program can require up to 6 confirmations!)
• If Vista doesn't know your devices, finding drivers is a chore... I had to find new drivers for my video and sound, and it wasn't easy (all my friends who rip on installing Linux should try installing Vista sometime...)

More to come as I play around with it... hasn't crashed on me yet, which is a big plus :-)