at&t you can talk and text and surf.. if your on the web with verizon it can go to voice mail or so im told....
i have had both providers but i went to at&t for the iphone.
I was there this past weekend and had issues in all the parks with and Att iPhone 4. Texting and making calls was not a problem but trying to email pictures to my grandparents and updating Facebook I had major problems. It was a hassle trying to do anything that involved data.
Just curious, are you choosing a carrier based on just WDW coverage? If so, you must be devoted!!
I can't thank everyone enough for all the great advice!
More importantly, when I'm in Caldwell, my AT&T service works fine, as does it throughout North Jersey and along the I-78 corridor when I am commuting from PA. Both Verizon and AT&T drop crossing the river.
If you are in NYC very much, you may find AT&T a little frustrating when the network gets heavily loaded.