I hate Windows. XP, despite being relatively "mature" as operating systems go, is about as secure as a bank vault made of drywall. You trust it to keep your things safe, but anyone with a good right hook could break in if they wanted to. I have been, and continue to be, a huge advocate of OS X, but even I concede that an OS limited to one hardware platform is lunacy.
That being said, I have to say I'm impressed with Windows 7. I tried upgrading my home PC to vista a while back. It lasted a week. An upgrade from XP took no less than five *hours*. Then there were issues with drivers I couldn't resolve, one of which was with my network card, which meant I couldn't download driver updates. Fortunately I had another computer to use to download them, but imagine my nightmare if I didn't.
Last night I installed Windows 7 beta. It took about 45 minutes for a clean install, and the only things I remember it asking me for were a username and password. Then... it just worked. No driver headaches, no security screens hassling me every two seconds, no spending hours turning off Aero components to make the system faster. The installer either had all the drivers it needed or downloaded the ones it needed (it's all transparent, so what do I know?), it didn't open a bunch of widgets that I didn't want (or have the power to run), and the security warning settings were set to a very reasonable level. I didn't even need to download special display drivers to handle the projector I have on the second video head -- it handled the independent resolutions beautifully. And within minutes of loggin in, I was watching Futurama DVDs using Windows Media Player 8 without codec warnings... and the playback looked better than VLC Media Player under XP.
I'm still installing software, so I may yet come across things that won't work under the new OS, but I understand it's a beta. I'll give it some slack. But frankly, at this point it doesn't need any. Win7 is what Vista ought to have been, and Microsoft knows it -- hence the extension of WinXP support. I'll be very sad to see Win7 Beta expire in August. Here's hoping I can afford the real thing when the time comes.