Best carrier for midwest USA?

[blibli]

I'm eager to use my Cosmo Communicator and I've had it for a long time, but I've failed to use both T-mobile and straight talk plans! 
What is the best compatible carrier for mobile internet on the Cosmo Communicator in midwest/nationwide USA? I can't find answers anywhere.
In love with the keyboard! 
Cheers! 

[vldmr]

I use it with ATT in midwest. Works reasonably well