I upgraded to 2.3 last night. I am having more HDMI sync issues with my Sony TV. The picture goes white noise frequently when the screen is static, at disc load and at menus. Didn't do that before.
From an SD audio viewpoint. I have a nearly unique DTS Demo DVD #2, which has its DTS track within the PCM track (before DTS was formally included in the DVD specification). 2.2 would mostly play this audio track with occasional hiccups. I cannot even get it to start playing with 2.3, so the player is altering the PCM tracks even though I have set it up to pass bitstream and not downsample. DTS Demo #3, which is the first DTS demo disc with DTS on a flagged DTS track plays fine.