The beta is as smooth as any normal version, cool features wonderful new concepts.And it really looks like one for the future. The Collaboration tool and also IE and support for both 32 bit and 64 bit applications, and ability to run IE in both 32bit and 64 bit mode are real cool. The inbuilt phising filter,antispyware and Firewall have beefed up heavily.The security features have improved vastly.And cooler vista doesnt allow any software to run in admin mode without ur permission...so virtually denying spywares any control at all.
I got nVidia drivers for vista (yes most hw manufacturers already provide vista beta drivers).Even if vista installs ur driver I recommend you to download from hw manufacturer.Most XP drivers will do for Vista as well. Diagonistic tool in system menu recommends ur hw changes and driver updates and also suggests reasons why your PC is slower.
My recommendation for Vista (minimal)
Any P 4 or AMD XP or AMD 64
atleast 512 MB RAM(if you have a good ie 128MB or above graphics card)
128MB or above graphics card(aero compatible)