1. Buffering is your phone having played everything it's downloaded, and waiting for more to come down. It depends on your connection to the server, not on the app.
2. There are apps that play some stations, some that play other stations, but none that play all your local stations (because "your" can mean anywhere in the world).
Look in the Play Store, pick a free one that looks good, install it and, if you don't like it, uninstall it and go on to the next one - until you find one that you like. (But again, your choice of app will have nothing to do with how often it buffers.)