I've tried T-Mobile and AT&T. Both carriers were substantially worse than VZ for mobile data speeds and dropped calls. Not just a little. Tremendously worse. The LTE on them was slower and more intermittent than VZ's 3G coverage.
The switch back to VZ from AT&T (after just 3 months) cost me hundreds of dollars, and was still worth it. (Thankfully T-Mobile had a weeklong trial program that saved me from going through with that switch)
VZ gets away with higher pricing and abusive customer support because their network is unmatched in my opinion. My experience is obviously anecdata, and I don't live in a densely populated city, so that may be worth noting.
In my market, NYC, VZ is by far the best provider. It has far more spectrum than AT&T, which esp for Manhattan is really important because of the density of people. Moreover, we have many large steel and concrete buildings and VZ gets the strongest signal.
Data usage has grown dramatically and the spectrum availability in your market can make a difference. VZ, AT&T, and others have purchased AWS-3 Band 66 spectrum which they are brining on-line but the iPhone 7 and Galaxy 7 chips don't support it.
It is 10 AM ET and I just ran a Speedtest in Upper West Side Manhattan and have 41 Mbits/sec down and 6.5 up on iPhone 7+.
On iPhones, install the VZ App, install the widget, get the Omnistat app and that should help with knowing your data usage.
Cell phone service is a conversation where anecdata matters. The carrier you have must work in the places you visit. Unfortunately for you, that only seems to be the most customer unfriendly one, Verzion.
Where I live TMO data speeds are much faster than both ATT and Verizon (we have tested in the office with people on different carriers). TMO service is also better than Verizon where I live, and if you travel overseas at all nothing beats TMO.
The best part of this is that all of the big carriers are improving their networks like never before. Hopefully sooner rather than later, network coverage will not be a competing point.
