I haven't seen anything on the Exchange Active Sync support to fully understand what it's bringing to the table. If it's a port of the S60 Mail for Exchange app then I hope that it's the new client with improved integration. They finally bring subfolder support to Mail for Exchange with an improved interface. If it's a port of the S60v5 app then it's going to leave something to be desired. Lack of subfolder support at this point is pretty unacceptable. And there may be those that think that since it isn't targeted for the corporate market that this is okay... It's not. If you're going to advertise a feature, do it correctly.
As to PC Suite sync, you are correct about the field differentials between Nokia devices and Outlook. I've lost all kinds of numbers because of field differentials. They've improved it a bit but the real rule of thumb that I've followed to stay safe is to ALWAYS enter your contact information into Outlook and sync it to the device and not the other way around. This helps to maintain your data and prevent loss.