I personally do NOT like the Blackberry for the following reasons:

1) Hate the UI
2) Devices aren't nearly as customizable as WinMo devices
3) BB Email doesn't really have any advantage over Exchange Email w/Outlook
4) BB Email requires an extra fee for the carrier (if on a single user plan) or an expensive server if on a company
5) PIN syncing on a BB can be a PITA if you're trying to use it in *anything* other than a RIM provided configuration

After using a WinMo 5 device I couldn't imagine being stuck with a Blackberry of any flavor.