Humm, good question John.

I don't have an iPad - However Jaz BF does.
He uses wifi constantly when he is here, we have Road Runner Turbo + airport base station and he is always impressed about the speed.

Now since the latest up date his wifi only iPad - can use (hot spots) via his iPhone 4.

I have no idea, how much he uses this hot spot - according to Jazz, he does use it.

Anyway - if you have a wifi only iPad + iPhone - you don't need to get a 3G iPad. Unless your into Face Time Video ? ? not sure how that would work.