Good service in the cities but it can get spotty the more rural you go. Almost all major highways are blanket service or on affiliated towers.
Can't really complain when I'm paying $35/m instead of $90+.
That said next phone I'm going to try GoogleFi, as I heard their network is similar or better.
If you don't want unlimited, I can't imagine how Google Fi couldn't be better. It uses the T-Mobile network along with Sprint (and MetoPCS now?).
Just not great for moderate data users.