Couple of warnings:
The preview release contains a not very serious but very annoying cosmetic bug that cause Windows explorer to put a plus sign along side every folder (the one that is supposed to tell you there are subfolders that can be expanded.) As I said, not major, but visually annoying. I am told it is fixed in later releases.
Also, some web sites have not updated their sites to recognise IE6, you may have problems getting into some secure sites (like on-line banking, but then you wouldn't want to do on-line banking with a such an early release product, would you?)
Otherwise fine, but it can be a big download