can i switch back?

OK - I've wanted to use my iPhone on Verizon ever since the first iPhone came out and I've been grumbling about AT&T the whole time I've been an iPhone user. So, with the iPhone 4S I decided to make the switch from AT&T to Verizon.

And while I have seen an improvement with voice/phone calls (after years, I can finally talk on the phone in my kitchen!) I have only seen a slight improvement with data. And data is more important to me.

See, in my toughest spots, my Verizon iPhone is giving me a signal, but it's weak. It's more than I got from AT&T, but it's not enough to give me a decent data connection to the internet.

So my question is, can I switch back to AT&T? I had an iPhone 4 with AT&T, so it meant I had to break my contract early w AT&T. I think Verizon has a 14 day return policy, though I think I lose my activation fee after only 3 days.

I bought my iPhone 4S from Apple - preordered - but I suppose I would need to get the AT&T version, correct? And do I return the Verizon 4S to Apple? I still have my iPhone 4 so maybe I could switch back to using it until I can get the 4S (since I think there will probably be a delay while Apple makes more - it's got to be out of stock right now, right?).

Do you think I can get AT&T to reverse the early cancellation fee if I am coming back? Do you think they'll let me have my unlimited data plan back and let me go back to the way things were before the switch?