I have been using this since RC and couple of weeks ago Microsoft has come up with the BETA.
Tested in the following specification
Desktop Compaq Presario (1GB +P4(2+GHz) +40GB)
Laptop IBM R52(2GB +M(1.73 GHz)+40GB)
Its seems to be like working on a windows xp machine with a Vista look and feel.
Comes with dozens of drivers and you don't have to manually install anything.
Cool features of Docking around the screen as you drag.
File transfer and installing software's are much faster.
Boots up faster and wakes in a second from sleep(not as I do snooze several times).
Minimum 1GB RAM is a good start.
Choosing different network on the fly to protect your PC with firewall.
Drag a window right and left like wiping the screen will minimize all other windows.
New Taskbar will a lot of features.
Depends a Good Graphics card and doesn't go well with the normal ones.(My PC Sub score 1.0)
Aero and other tabbed preview are disabled.
Painting issues in the desktop rarely.
If some errors are thrown after installation it will not correct (do a clean install again)
If System hangs no way of using Ctrl+Alt+Del have to do a hard reboot.
Space occupied for installation 12GB after installing all the software's it comes to 18GB
I would suggest people using Windows XP can give a try to this.Its really yet another good product from Microsoft.
(Note:Beta download is free to use till June 2010)