The BES is great for syncing of emails however it is overly dependant on RIM. Any hickup on their end and everything stops. Very hard to explain to non technical users who think because Outlook works and their phone works that their blackberry should work.
One of the best features we have found is that the BES stores all the user settings from the blackberry. When my own blackberry died, all I had to do was active a new device and all the settings, notes, memos, calendar, saved emails, backgrounds, alarm settings, ringtones etc all came on to the new device.
The remote wipe is another very good setting for protecting email.
If you are the BES admin, it is safe to ignore most of the warnings that it puts in the event log. RIM don't know how to do logging properly.
Also regarding the problems with those in the domain admin group. http://support.microsoft.com/default.aspx/kb/912918 contains all the information you need to fix it. The problem is not only restricted to Blackberry.