I have had Sprint for 3.5 yrs now, it seems comparable to my work phone 2 yrs ago we had T-Mob - currently AT&T
the all share each others cell towers ....
[I like closer to the beltway near National Harbor]
Sure, you'll get a connection, but it might cost you the roaming charges and be of lower quality (i.e. 3G instead of 4G)
Verizon is probably the most expensive and that higher cost is driven by the demand for bandwidth.
Which cell phone carrier is better is like debating which restuarant is better, it all depends on what your expectations are.
The old ads that AT&T and Verizon ran comparing the two networks seemed to contradict each other, but the fact was they were using two different statititcics to argue who was better. AT&T claimed to be the largest network based on the number of people who were in their coverage area - which was then focused on major metropolitan areas. Verizon claimed to be the largest network based on the area they covered - they had more of the country covered.
When we first moved to St. Marys the only service was Bell Atlantic (now Verizon). I think it was the Sprint store in Waldorf that tried to sell us on their service EXCEPT that it didn't reach much further than Charlotte Hall.