An iphone?

Before I assist my cousin for his Philadelphia job search, I have been contemplating to get an iphone. Actually it's a toss between iphone and a blackberry. Really no idea which one would be better. A friend is selling her iphone at a very good rate so I'm tempted to get it. I know how much she's taking care of her things so I am sure the phone she's selling is of good working condition.  Now, i practically do not know how to use an iphone especially its touch screen feature but i like the idea of being online all the time.  I am actually thinking of a blackberry instead. Which do you think is better?