Difficult to advise because like all Betsa there are potential problems. The IE7 RC1 appears to be very close to the final version which is expected to be out before the end of the year.
I decided to try it in this form, obviously creating a restore point (in XP) before doing so. The MS site makes it clear that if you do not like IE7 RC1 then an unistall will roll it back to IE6.
Can you meet the sytem rquirements though? click here