Hi
Depends on how much typing you're planning to do.
And how well you like the T9 or can hit the full virtual qwerty on a small display.
I do write much more on this small screen, both with the T9 and various qwerty, then I planned on doing. So it's possible.
I guess that you might be able to use two fingers on the pro with keys. So that would give you more speed then one finger on a virtual T9 or qwerty.
My experience is that the T9 takes up lesser space then the qwerty ones on the screen and you can see what you're writing. It's good at guessing right and learns your words and use them well. It takes some time getting used to if you've not used T9 in a while.
The pro will give you more/all space on the screen to see what you're writing.
I've tried a few virtual qwerty keyboards but for most of them the screen is too smal (for my fingers) and not written for the screen size so they're not precise I think.
There's one that I find better then the others.
The "SlideIT" keyboard. It's originally a "swype" kind of qwerty but also support singel-tap on each key. I find it more precise then the others and easy to hit the right key with lots of air between them.