OK, .22 isn't solely about UI...
From the Release Notes
* MythTV UI ported to new MythUI library with all new capabilities
* VDPAU Video renderer and decoder for hardware accelerated playback of H.264, MPEG-1/2, WMV, and VC-1
* DVB-S2 support
* Support for the Hauppauge HD-PVR
* HDHomeRun Multirec support
* New channel scanner
* All new default UI theme and OSD theme
* Mythvideo now has season/episode support, fanart, banners, screenshots and much, much more
* Added Automatic Prioritization to the scheduler which uses watching behavior to automatically increase priority of shows that are watched close to their recording timeslot over shows that are delayed for longer periods of time. See  for details until the wiki page is populated.
* Windows port improvements
* Mythbrowser now uses webkit and has no dependencies on KDE libs
* MythMusic has fewer external dependencies
* MythTV switches from Qt 3.4 to Qt 4.4 libraries  (No changes affecting end-user!)
* MythPhone has been dropped