I have the curve and average about 100 incoming emails every 2 days -- only about half of these need replies. I find it so easy to do emails that I usually don't bother going to the computer -- since I manage 2 business and 1 personal email accounts it's just easier to do them all from my BB, unless I have to send a spreadsheet or other data that is on the computer. And I'm so used to typing on the BB that I find it hard to remember to put in capitals etc when I'm typing on a computer. I do know a lot of people who've had trouble with their iPhones after they've been dropped -- my DD uses my BB all the time and it has been dropped a lot with no issues. My brother is a lawyer and he has a 2 y.o. -- he also has the curve and would say the same thing (in fact, he's the one who convinced me to try it out in the first place)
Regardless which one she chooses, I find the BB has really saved me a lot of time. My job is pretty flexible, but I can at least take care of my emails while I'm waiting around at DD's dance classes, etc. Add to that all the time that you wait on line in banks, etc. and I'm probably saving myself about 10 hours per week.
Just have to add that even though one brand or model might be technologically superior, it really is a personal choice. For example, I know a few people who are so used to texting on the old triple key phones that they just can't get used to having a QWERTY keyboard.