Windows 7 RC1 will be released on MSDN on april 30th. There is a very nice review/ preview on the windows supersite. From my experience so far (from the public beta): it’s very slick and snappy. The ui is a lot better too, especially the task bar. It stacks the programs in a much nicer way, and you can easily switch between windows etc.. But read the extensive review below for (much) more info .
But Windows 7, in release candidate guise, is already a towering achievement that casts Windows Vista immediately in its shadow.
Microsoft’s Windows 7 Site
Windows 7 RC1 Review
One of the things you really miss, once you have also used a mac, on windows is Quicksilver. It’s a program that lets you start programs and open documents incredibly fast. Just hit ctrl-space, type a few letters and usually the right program boots up. This would be especially handy on windows, when you’re like me and install and try a lot of programs and your startup menu is totally cluttered and you cant find anything anymore ;).
Looks like Colibri does about the same thing, just recently started using it and seems to work fine, this blog post mentions some more programs that I am definately going to try.