From v2.2.1 on Transistor uses a different playback library ("ExoPlayer"). Radio stations now should load faster. Additionally Transistor now supports more audio formats on certain devices.
Changing the playback library is a pretty huge operation. Although the new version has been beta-tested, there still might be bugs in v2.2.1. If you stumble upon one, please report it on Transistor's GitHub page.
THX & have fun