I probably would not want to involve with Microsoft on a pager. I like the separation... I think that BlackBerry would be the best because I have seen many deaf people carrying a BB in their pouch. Note: One of the BB device is more stable and stronger than the other BB ones.
For the cost, it depends which area that provide you for the service.
I was told that you can use the BB on the relay service. SK has one, but it has to go to one company, and it has to go to another company to hook up the relay service. The BB goes straight to the relay at once. I am not sure what she means that it is free to email to anyone unlimited. I believe that it cost you per email.
She also said that it has a game on the screen, and it cost 10 dollars per month, and she doesn't want to pay that fee so she never use the game.
I went to the ASL Expo, and I learned that a BlackBerry with a curve button is frail if you drop it on the floor by accident. Most insurances are not covered in a water accident. So, just don't use it awhile you are sitting on the toilet. (Rolling up my eyes.)