My wife and I use Straight Talk and Verizon phones. The Verizon phones (CDMA) are almost useless for business as they frequently have low signal or no signal. We use a Straight Talk GSM (AT&T) for business. It receives a signal everywhere we have been in the U.S., and we have never missed a call from our dispatchers.
Try the Straight Talk service, I think you will be happy. But be sure to choose a phone with a model number that ends with a "G" (G for "GSM). Like I said before, we have found Verizon (and other CDMA phones) to be almost completely useless for business.