I've been with AT&T since 2000 (AT&T, Cingular then AT&T again), finally decided to switch to T-Mobile in 2014. I've realized my big mistake and T-Mobile was still just on its way of improving their service at the time.
So, when AT&T and Verizon doubled their data in Oct that year, I switched again, this time to VZW. Had them for more than a year, and loved their service. Everywhere I go, there's just signal, just like Steve Jobs always says, "It just works.".
When I visited National Parks in the West, most carriers have no signal, VZW has decent if not full bars of signals on all parks I've visited.
Then decided to try T-Mobile again last year, they've improved, A LOT, but they still have a lot of dead spots in between. They're not as well engineered as VZW is when it comes to signal penetration and propagation in a lot of places in and around my metro area.
Being that I need signal all the time specially where I drive from one place to another around a 200-300 mile radius, I switched again to VZW. I got the 24GB plan for 3 lines plus 4GB bonus with a corp discount. We use over 20GB per month, and that's with trying to limit watching online videos and video calls.
So this unlimited plan works really well for us. Now we don't need to limit anything we use data with, and my bill only increased 14.20/mo, which I made other members of our plan pay for it. Lol