Well the OP must be the unluckiest person in the world. Because I travel to several cities a week and AT@T is fast every where I go. Verizon is molasses in comparison. Where do you live?
I get 6Mps down on HSPA+ on the regular where I live and I average 3Mps or usually more than that everywhere I go. Verizon 3Gs tops out at under 3Mps theo. with real world speeds in the 2Mps or 1.5Mps. And that is the fastest it goes, as good as it gets so to speak for the iphone on Verizon since LTE is not available on the iphone nor will it be for the iphone 5.
And let's not forget the fact that ATT's coverage is going to get a whole lot better at the end of the year once they get Tmobile's towers that already have HSPA+ with 24Mps downloads. And then the coverage will far out pace Verizon. Not only will ATT remain faster, but they will have better coverage too.
ATT will have HSPA+ for the iphone 5 which can go up to 24Mps while verizon will be stuck with 3Mps with real world speeds half that. So for the foreseeable future for the iphone 4 and 5.
Take your phone back while you still can. Verizon is not the carrier to be on if you want fast data speeds on the iphone 4 or 5. Verizon data speeds on a iphone is garbage. Not to mention the added fact that you can use voice and data at the same time.
Knowing these facts how can you be happy with going with Verizon?
https://www.macrumors.com/2011/06/02/iphone-5-att-4g/
"The implications of an HSPA+ iPhone are significant in the United States, where Apple presently offers a separate CDMA iPhone running on Verizon. Even with both current models of the iPhone 4 limited to 3G networks, AT&T's HSPA data network is already faster than Verizon's EVDO data network. That disparity will be magnified with the next iPhone as AT&T users will be able to experience download speeds in the range of 5-10 Mbps under HSPA+ while users on Verizon will remain stuck on the carrier's current 3G network running in the neighborhood of 1 Mbps. "