You can get build 5728 from
http://download.windowsvista.com/preview/rc1/en/download-5728.htm
Edit: this build was available only for a short time - this link is now dead, and 5600 is the only one available to the public.
As for installing drivers, I didn't bother on my iMac. Everything seemed to work ok, not that I spent much time with it. I'm not particularly impressed.
Take away the eye candy, it all looks like a reskinned XP. All the menus look the same, the start button is rearranged, the sidebar (ie. Gadgets) is so incredibly annoying I turned it off as soon as I could find the option to do so, they still use the retarded A:, B:, C: etc drive labels and the backslash for directories, UAC is still too intrusive. They could write a similar skin for XP in three months and 99% of users wouldn't know the difference.
I know that there's more under the skin -
http://en.wikipedia.org/wiki/Windows_Vista - but I'm just looking at what non-techie users would see. If I were exclusively a Windows user, I wouldn't see anything to make me want to upgrade.
I will be using it once it's released, since I'll need to test my code on it (as well as XP, various Linuxes and OS X), but my employers will supply a PC with it installed, and it can sit under my desk unused except for when I'm testing something.