If Danger could create an OS for other devices or get out from under Tmobile and really ramp up the feature set...
The Sidekick was solid as all heck, had the best keyboard of any smartphone and was more thought out and intuitive than the blackberry by quite a bit. The BB OS is very menu driven and the sidekick was mostly button and context driven.
Being able to adjust settings for a program from within that program makes sense and being able to just plain use the device full tilt without worying about your SMS and email being randomly deleted should be standard.

All of that aside there were features on the blackberry that made me upgrade and overall I'm glad that I did. If and when Danger decides to take their next phone seriously I may reconsider but their slow pace of innovation pretty much forced me away.