I am currently running Win 7 Enterprise Build 7600 90 day trial. I had previously ran the earlier candidate and made the commitment to purchase it when released 10/22/09.
I have installed the 64 bit version on a very capable desktop and it is wickedly fast.
I do have a couple of concerns...
64 bit
compatibility
desktop performance
document access
document recovery
drivers
help request
hyperlink
installation problems
msoffice2007office suite
open office
product purchase
software compatibility
software issues
technical support
trial version
upgrade
user experience
windows 7