I have Verizon. I've considered switching to a smaller carrier to save money but I never do. I've found Verizon works well in remote places. I took a neighbor to Colorado a few years ago on a hunt and he had an alternative company that he said used the same cell towers but quickly found out that wasn't completely true. He couldn't make or receive a phone call where we were staying or hunting and I had to drive him into town every couple days, so he could talk with his family. That's the only experience I've had with them but enough for me to keep paying the larger bills.
We had xfinity mobile after having verizon for years. They run off of Verizon’s towers and in our area I couldn’t tell much of a difference in coverage. You have to have their internet to get a deal on the mobile lines. We just switched to Visible by Verizon yesterday. Coverage at home and on the property seem pretty good, and service is typically spotty out here. Down side of visible is they don’t offer family plans so my wife and I had to sign up separately.
Been using Consumer cellular, It has worked everywhere I've been so far for 4 years. We don't have any high speed providers, so Starlink and Hughes are it. The only issue I have with Consumers is the 50 Gb cut off. So it is not unlimited data as stated, but most are not.
We have had Verizon forever, got sick of lousy customer service and high price. Switched to Consumer Cellular, phone works the same with great CS and a lot cheaper.
I look at my cell as something I just need to work and the combo of current monthly cost and my lack of price sensitivity keep with ATT. I would be much more interested in a value prop of more coverage or more reliable coverage than one about reduced cost.
But I also am running a business and its hard to be unavailable, I could imagine my perspective changing if it was purely persona use.
Switched from Verizon to US Mobile. No regerts. I run on the Verizon network at a fraction of the cost. Can pick Verizon, TMobile or ATT network to use. I paid for 12 months up front...I think it was like $300ish back in late winter.
In terms of towers they are all the same big companies you'd be using. The smaller companies may offer cheaper rates, better/worse customer service, etc. but you need to pay attention to what level of prioritization they get on the towers they are using. Off brand company X might have low tier priority on "verizon" where as off brand company Y has nearly as good as access to "verizon" as a plan with verizon.
I am on xfinity now (verizon towers) after ATT for years. Around home ATT coverage had gotten piss poor with their towers being overloaded for the user base which was unacceptable for the premium prices they were charging (go to an event at the park and you literly couldn't send out a text message due to lack of capacity). So far so good with xfinity.
I have had Verizon for 20 yrs. Never had an issue. Literally everyone I know that switched form ATT or Verizon to a smaller carrier has had issues. Service sucks in places it didn't or stupid things like texts not going through to previous contacts. I've never talked to anyone that switched and was happier with the new company.