I haven't used the rest, but I just think that for the money it would be hard to get anything better(iphone is obviously more expensive).

I think the 8520 is also the only Blackberry currently out with a trackpad(which is like the mouse pad on a laptop, only smaller). The rest have rollerballs, which are prone to problems. Very easy to use. You get all your hotmail(or whatever other account you use) emails etc straight to the phone like texts, and there's loads of apps etc for everything you could need.

Instant messaging is easy too. There's an MSN app, Facebook... loads of things that bypass the need to go on the net and sign into websites etc. Obviously you have a qwerty keypad too, which is very quick and easy to use when you get the hang of it.