I supported 15 users with blackberries (and carried one myself), I've configured/maintained BES & blackberries from multiple providers.
I would not use one for personal use (with the possible exception of the 7100, if you like it).
As much of a tech toy lover as I am blackberries do NOT excite me. They aren't flashy, the displays aren't that attractive (and they're low resolution), the interface is somewhat cumbersome at times, they have no multimedia capability whatsoever, they're bulky, not particularly expandable, need I go on?
For business use though they are great. I don't care what anyone says about predictive text for people that send the majority of their correspondence via mobile device a full keyboard is essential. They're great for reading & sending e-mail, integration with Outlook (Contacts, schedule, etc.), opening basic Office attachments, etc. With BES mobile data they also work relatively well for rudimentary internet access. It's slow as hell & you can't do much with it but if you need a map, driving directions, or a quick google search to verify information they can handle that.
Viper GTS