I'm giving it a 10 as it is an awesome adventure and still stands apart as being a unique adventure for PCs and DMs.
Hopefully, I'll be running it with my Epic party as it seems that ToH (and RttToH) is an excellent challenge worthy of their level. That being said, someone on here once mentioned that, if played right, a 1st level character could do it all, save destroying Acererak. Likewise, and epic level character is by no means guaranteed success in this enterprise.
For the naysayers out there, yes it is a big, huge death trap. However, it is not undefeatable and any PCs who can make it thru are awesome gamers. (Not that you couldn't be awesome w/o beating it, but beating it definately elevates your level of play.)
-AoA