You can do that on Verizon as well, provided you're on their 4G network, which is like 97% of their data service area.
I was with AT&T for about 15 years, but just switched to T-Mobile. Coverage definitely is not on the level with AT&T or Verizon, but it works for me at home, work and school. I know that heading out to the coast or the mountains, I won't have service, but for $90 a month with putting my dad and my brother on my account, I can live with it. I'm okay with springing full retail for devices when I need them.