It's good you did not include the iphone 5 because it has not had good reviews from people I know,
Iphone 4 is not bad though pretty much depends on you isp/ at&t is not a good one. which I'm stuck with for a little while longer/ 3g yuck. wifi works wonderfully though.
So it's more of a connection as to how good or bad a "smart" phone is,
I might try a android next time around with a different cell service.
If you do get a iphone 4 or 3 be sure to get a good cover they are the slipperiest darn thing I've ever touched/ glass a kid would drop it a less than a second