I'll say right off that I know very little about Blackberry devices. My little brother has used them for years, and loved using them, but I've never so much as typed a word into one. But just a couple of days ago while riding a bus, the woman next to me was working on a large document on her Blackberry. The thing had a HUGE screen with gorgeous resolution and saturation/contrast. Shades of iPhone screen quality there. The predictive text input with the on-screen keyboard seemed to just breeze along for her fingers, responding instantly to every character tap, though her input looked rather vague, without obvious effort being put into accuracy. She was jumping around to various places in this thousands of words long doc, cutting and pasting text blocks, entering new sentences, and all the while keeping her infant daughter in the stroller next to her entertained with conversation and snacks. She interrupted her editing a couple of times to look at email, then returned to where she was in the doc... not sure if those things allow multi-tasking, but it sure looked like it. Zero delay, I mean 1/10th of a second at most when switching applications and nowhere near that long with input.
I've seen a lot of iPhones in operation - my clients generally use them, as musicians generally seem very happy with Apple products in my experience - and have never seen this kind of speed, though an iPhone can generally appear to run more smoothly than any Windows Mobile device I've handled. Seems to me that with a user experience like I saw the other day, and a brilliant, beautiful screen (at least 4", perhaps bigger), Blackberry is likely to be popular for a while yet.
Gerard Ivan Samija