Anyone have one, and if so, what would you say are the biggest pros/cons to having one?

They are more pricey than a laptop, but have all those apps to choose from to personalize based on needs.
I am considering, but was wondering how others like theirs, and what recommendations for a new buyer they would give, especially around getting the 3G version, or sticking with wi-fi and using the iphone to access data when on the go.

TIA!