This is a very interesting subject, and one I'm very experienced in. The cell phone business itself has been changing and evolving every year. For us cell phones are more than just internet or a phone it is the major reason we are able to full time in our RV. You see about 1 year and 4 mos ago I was tired of all the big 4 greedy carriers and I sought out to take control of my wireless. While searching I was trying T-Mobile Prepaid, Simple Mobile, Straight Talk etc. Then we found this new company which had a great offering and we switched. To our total surprise this turned out to be the best thing ever and we now have a 3,000/mo income and free cell service from this carrier. No other cell phone company ever paid me for telling other people about their service. So as life would have it I got disabled and lost my Engineering job. While this was hard and required a big adjustment it was this extra income which suddenly became our only income (at least for a while). Now that I have my disability income we have decided to full time at least for a while, health permitting. So as you can see phones and cell service can mean so much more to some of us than others. For us it is our life.
Now I will agree with others that Verizon has the best overall coverage, definitely better 4G, LTE in rural areas. AT&T is a close second. T-Mobile while great in Metro areas does lack in rural areas. This being said they are making huge improvements to their network. Sprint Don't even bother IMHO.
What we use: For internet Only we use a Verizon Hot Spot.
Our Cell Service: 3 Lines on Solavei @ 29.00 unlimited Talk and Text. Of course they are all Free now.
We personally don't like contracts and being locked in to one option. But this is just us. What ever you choose you might look in to a prepaid option for a month or two to see if it works for you.
