I really Really REALLY dislike touchscreens. If I don't have to touch the screen the screen is going to remain in better condition. No brainer, right?
Do you use the media features on the Treo? What's its primary use? If phone and email (and organizer) then you will love the BlackBerry. If you use it to play music or use the camera, you may miss those features, but possibly not enough to remain on the Treo platform or go with the Q.
WinMo is at best inelegant and at worst buggy and slow. Simple things like keyboard shortcuts are not the same across the UI (inexcusable).
IMHO, Microsoft wants WinMo to function like a computer (that is desktop or laptop). I already have a laptop. I want mobile email and voice, my calendar with me and a place to note spending. I do not need a huge operating system (poorly designed) for that. I just need my BB.