This is one of the most annoying things about BB. I can't tell you how many times a sales guy has told one of my users, yeah, it works perfectly with Exchange! and then my user comes to me and we tell them it can only sync their email inbox that do not have rules. Then I have to tell them it requires BES to get their contacts, other inbox emails/subfolders, and their tasks/calander. Fine for just one user, since they offer it for free, but usually requires many people. I hate BB for this reason...
And a side, note, Palm OS and iPhone both have exchange/activesync modules. Symbian also have an Exchange solution available that works reasonably well. And most of the major phone manuafactures have Exchange modules that you can either add or are built in.
http://www.microsoft.com/exchange/2007/evaluation/features/owa_mobile.mspx
So pretty much just BB are the only ones to say, "screw Active sync!"