Your first step should be asking your friends and neighbors about their provider and its coverage. If, for example, there are dead spots in areas that are important to you, you'll want to know that before you decide on a service.
You can also check each provider's coverage maps on their websites, though first-hand info from actual humans you know is preferable.
From that point, you can compare handets, prices etc. but if you can't make or receive calls, or experience dropouts or other anomalies, those factors will fade into insignificance.
Good luck and let us know how you make out!