Very interesting read, particularly in where the service providers are expanding their network. It speaks a lot to the each company's priorities and confirms a bit of my personal thoughts on each of the companies.

Verizon - I had Verizon service from 1996 through 2008 and the one thing you couldn't really complain about where I lived was reception. Billing issues and customer hostile behavior were the reason I ditched them [0] but there wasn't a moment I can recall grabbing my phone and not having a solid signal everywhere I traveled in the US. They were laser focused on providing a modern, reliable network. Quickly moving to increase capacity - they've always had a pretty solid focus on providing a solid network.

AT&T - I have a personal hatred for this company after numerous problems with services other than mobile. Their attitude was best summed up by a Saturday Night Live skit[1], "We're the phone company. We don't care." I've never used their services if I had a choice (that was probably the single biggest reason I didn't purchase an iPhone, originally) because every time I've been forced to use one of their offerings, a variety of service related issues (not helped by their customer service department) has made them unavailable for long periods of time. It's disappointing to me that they seemed to think it would be a good idea to halt wireless expansion and redirect that money to the DirecTV acquisition. It seems that couldn't have come at a worse time considering the rapid expansion of wireless.

T-Mobile - This was a little surprising and appears to have not been intentional. They had no choice but to setup a large number of cell sites due to the limits of their spectrum. I was a T-Mobile customer (and, technically, still am one now that I'm on Fi) and I've never had real problems with their service outside of 4G taking a while to get coverage in all but the most densely populated areas.

Sprint - As a Fi user, that's as close as I've gotten to Sprint service. They had an interesting network in Michigan. The coverage is spotty in areas that most other networks are well covered and good in areas that aren't covered well by anyone (there's an area of the thumb off of M-25 that is dead to AT&T, T-Mobile and Verizon but works on my Fi phone). Legacy equipment is all over their network, likely because replacing it is beyond their financial means at the moment. I don't see it getting any better. They're a fourth player in a market with barely enough room for three. In a healthy market, you'd expect a player with poor service to be substantially cheaper but last I checked (and I'll admit it's been a year or two), there wasn't much of a price incentive for accepting the lower service quality.

[0] Technically, I was an AirTouch customer in 1996 until whenever Verizon purchased them. Back in the day, they had the best network in the area I lived in. My bill was around $150 and this put me on the high end for their already expensive service. At some point they put people above a certain service plan into an arrangement where dialing 611 resulted in being connected, within five rings, to a human being. The first time I did this after they switched it around, I stammered a bit due to not getting a seven-layer phone tree. Dealing with their perfect English speaking CSR staff was a delightful experience and it was gone shortly after Verizon took over.

[1] https://www.youtube.com/watch?v=CHgUN_95UAw