This closely mirrors my own experience with Republic Wireless. I have been using their Moto G on the $25 a month plan for about a year and it has been flawless. The only wifi networks I use are at home and at the office (and the occasional free wifi at a a coffee shop, hotel, or the like) but that covers something like 70% of my phone usage anyway. I stream Pandora over the cell network every day while commuting to and from work and I have never even come close to data cap. Call hand-offs between wifi and cell and seamless and the phone is very smart about avoiding bad wifi connections or access points with blocked ports.
The only real downside is the limited selection of phones. The Moto X, Moto G, and Moto E are all they offer so if you are in love with the latest iPhone or Samsung Galaxy you are out of luck. However the Moto phones are reasonable high end, mid range, and entry level devices respectively.