Depends what you value the most. Blackberry will just work, but will be MUCH more limited in functionality than the TREO. If you're a Palm user who just used it in the default configuration and didn't install lots of 3rd party add-ons for various IM's, improved calendars, etc, buy the BB. If you like to have things just "so" then go with the TREO. The TREO - I guarantee - will be less stable than the BB, but not unusably so. My TREO reboots about about once a week. The BB I had rebooted .. ummm .. never. But I like the TREO much better because while BB email is great. I found it's contacts and calendar to be sub par. Also, the BB I had did not sync contacts and calendar over the air. Only email was pushed, not the other PIM items. That was the deal breaker for me. Perhaps BB does push of these items today, but it didn't 2 years ago.