They are hands down the most reliable cell voice provider with the greatest coverage. Their customer support is not great, their prices are too expensive but they are reliable.

I don't have a smart phone and use my cell only for voice so Verizon works great for me. Sometimes I travel in US and my wife's AT&T phone loses coverage while Verizon still has a strong signal. It is almost never the other way around.

Hardware-wise, I believe, Verizon own most towers as well. Often other carriers rent space on a VZ tower.