It depends on the way or number of "phone" calls you make or return each day. I like my iphone for all the things it does well. But prefer my Blackberry's for making and returning calls. On line information, check stocks, posting of Ebay/Pelican, reading the NY Times are all fine on the iphone. But taking or making 20-60 calls a day or typing lots of replies I feel is slower on the iphone and best done on my blackberry. Also the spell check seems to work better on the blackberry system vs iphones. I'm a high minute guy with (3) phones at all times (I know>no life; but long time Porsche guy) burning 3000 minutes a month on average. But thats the world of business, it's about "instant" communication it seems.
Hope the input helps
art