Got powerdvd working, imo its much smoother and lighter then tmt. But in some ways buggier, some movies dont play in powerdvd that work fine in tmt, and on my dune bluray player.
Powerdvd 11 works in xbmc if you use bluray folders, powerdvd 12 will not.
Basically xbmc and I think mce (never used it but im told it does) look toward the index.bdmv to launch blurays if you use a bluray folder structure.
For whatever reason with powerdvd 12 they removed that ability.
Powerdvd 11 however they do have the ability to launch a bluray folder from the index.bdmv file.
Powerdvd 12 does allow you to manually navigate and open bluray folders, but thats useless, nobody using xbmc wants to manually navigate folders to open a movie.
Anyway in my testing powerdvd 11 was much smoother, lighter, and stutter free by a mile at 23.976. If you use tmt only at 60hz, then its not an issue, but if you use proper frame rates for blurays (23.967) it has way more stuttering.