straight talk wireless at wally world

I have had it for a little over a year with my iphone 4s in the Phoenix, AZ area. The internet is hit and miss, and only 3g. They supposedly use Verizon and ATT towers, but in remote areas where I had phone reception with Verizon, I have no service at all. There are a ton of dead internet zones everywhere, and I am pretty dissapointed with that.
The price is right so I will use it for the next 9 months till we leave full timing. Then, we will go to a different service provider.