Always select your carrier first based on real world coverage where you need it.
Don't assume that all physical keyboards are the same. Make sure you're trying out any device you're considering in person to assess your preferences for physical characteristics -- not only the keyboard but size, weight form factor, screen, etc etc. Selecting a device isn't a one-size-fits-all thing. In other words, not all ex-Blackberry users decide to go with the same Android device.
Don't overlook keyboard apps. I was a BB 8310 user and had a strong preference for physical keyboards at the time which led me to select the Droid. The Droid has a terrible physical keyboard and an awful stock virtual keyboard. Swype made the virtual keyboard usable for me and I rarely use the physical keyboard on my Droid. I just loaded Cyanogenmod 7.03 on my Droid and its virtual keyboard is better than that in the stock Droid ROM but I'm still evaluating it for myself. YMMV, of course.
Any other requirements? Your needs/wants are what you need to use to narrow down the options. What other type of info are you looking for? I can safely say that I wouldn't consider switching back to a Blackberry unless RIM can successfully implement some major improvements. My criticisms are pretty much the same old criticisms that RIM has been receiving for ages (basically "too little, too late").