Before I had the Samsung, I had the BlackBerry Curve 9300. I actually quite like to typing experience on that( although the only other experience of typing was rubber dome, or the wii onscreen keyboard which is possibly the worst keyboard I've had to use to this date.) and would possibly consider getting a blackberry again just for the typing.
It suppose it depends on how much typing on the phone you do, but I found it to be much slower and less accurate than an on-screen keyboard. For me, this came down to auto-correct, which despite it's faults really does a good job of keeping you on track if you type out very quickly, as well as the physical force needed to actuate the blackberry keys. I also don't think it's worth losing the screen real estate for a keyboard, and the fatigue on my thumbs became noticeable.
I do remember a Blackberry TV commercial a few years ago that showed this woman who apparently sent a thousand emails a day from her phone, stating "try doing that on a touchscreen". It made me think, there are only about 16 waking hours in a day... 1000 emails would be just over one per minute.
What she needs is a computer. //offtopic