Was with Verizon from 2001 until I got my first iPhone in 2010, when they were still exclusively w/AT&T (which is *wild* to think about, in hindsight).

AT&T was great, never had a single issue with them. Good prices, perfect service pretty much no matter where I went, and an unlimited data plan that I had been grandfathered into for a few years as unlimited data was going away around I dunno, 2012 or 2013 or so.

I went through 3 iPhones w/AT&T, at which point I was married and so it was time to think about combining our plans to save a few bucks. She was with Verizon, and between the two they were offering the best plan to switch so we went with them. But I wasn't thrilled about it. By this point all carriers had stopped $200 new iPhone w/2 year contracts, and forcing you to "rent" your phone which is something I loathe on principle. Also, the data was no longer unlimited like it had been w/AT&T since I started with them (which as I noted, wasn't really offered with any carrier at that time for a couple years, so this was just a general complaint about all carriers, not just VZ) so not only was I "renting" a cell phone but I was now forced to incessantly watch my data usage like I'd never had to do before. Which was obnoxious as hell so the overall experience was just brutal from day 1.

Within 3 months I was fed up w/VZ for the reasons mentioned above, and I saw a commercial for T-Mobile where they were offering to pay off your rented phone in full w/your old carrier if you switched, as well as unlimited data/minutes/texts for $120/month for 2 lines (w/Verizon I was renting my phone, with limited data, and paying almost $200/month for our two phones). So one day in a fit of rage (that day the data usage monitor on the VZ app was fucked up for like the 6th time since I'd made the switch, and was saying I was over my limit like 3 days into the month) I went to T-Mobile and made the switch.

T-Mobile was awesome - we were with them for 3ish years and never had a single issue. Additionally, we did a bunch of overseas travel during those 3 years and T-Mobile doesn't charge fees to travel internationally so we didn't have to pay like a $10/day fee like we would have with most other carriers.

Just last week we switched back to Verizon because we were both in desperate need of new phones (after 5ish years with the ones we had) and VZ was offering BOGO for the new iPhone 12 so it ultimately saved us like $900; and the monthly unlimited plans were no difference in price otherwise.

I'm not thrilled to be back w/VZ, they're my least favorite of the 3 carriers I've been with (never tried Sprint) but I couldn't pass up saving almost a grand.

All that said (and I know nothing about how coverage would be in your area; I'm in Boston and never had any service issues with any of the 3 carriers) my best overall experience was with T-Mobile, for whatever that's worth. Super cheap plans always, international travel coverage at no extra charge, "T-Mobile Tuesdays" which is a weekly offering of like a free coffee or some other benefit just for being a customer, I had Hulu free for like 8 months or so, etc. They seem to be the most consumer friendly of the 3 carriers in my experience.