It all depends on where you live. Verizon has MUCH better overall coverage, especially in rural areas. That's why it is a bit more expensive than the other providers. All those extra cell sites are VERY expensive to build & maintain.
Sprint LTE fades quickly once you move from their towers as they are still using extremely high radio frequencies. Those higher frequencies also have a harder time penetrating buildings. The other providers are using more favorable lower frequencies (yes even T-Mobile now is catching up) which provides a huge coverage advantage with fewer holes.