[margro]

@sdalton: switching across tuners won't really help. The current delays in the offical XBMC builds are unrelated to tuning times. It is the stream detection of the ffmpeg library that always analyses toe stream for 5 sec before the actual playback starts. Add to that the 2-5 sec from the backend for the actual tuning and CAM decoding (in case of encrypted channels) you have the 7-10 sec switching delay that most people report.

@nonob: yes the official 12.3 build has only "slow channel switching". The changes found in my builds are not yet accepted upstream and will probably not even be part of the upcoming XBMC. Gotham.

@javlin: the changes are still under review and Gotham is already in a feature freeze state, so they won't be included in Gotham unless a miracle happens
See for the current state of the discussion: PR3590.
Note that even without my changes, channel switches in Gotham will be 1-3 sec faster than in the official Frodo 12.3 build due other changes from Elupus in commit 4153310f31. This is mainly visible when using the MediaPortal addon in FFMPEG mode (RTSP streaming).
You can test this already using the current nightlies.