I have in my set-up Bryston BDP for very few days. I am used with Squeezebox interface since I have their player for long time
For remote I use Andoid tablet and smartphone
BITMPC and PMIX seems designed only for smartphone, the resolution on tablet is very poor. Out of them I like better PMIX, however I miss on its interface buttons for browsing for more music - you have to touch menu and after that you have option to browse by artist, album, files.
On tablet I tried Droid MPD and MPDroid. I prefer MPDroid because have direct button for browsing media, you can choose your default preference for browsing (by artist, by files...) and can display larger album art (in theory)
I failed to display album art (cover.jpg from music folder) so far on any of the apps. Sometimes MPDroid shows some album covers if is set-up to search on internet for them. I need to spend more time on this...
The feature that I miss the most is the way to play an album directly from the browsing interface. On Logitech interface I browse, open the folder, touch first song and all content of the folder become playlist and first song starts to play. On MPDroid is possible to do this only with long touch on the folder with the album, choose "add, replace and play". Probably I can get used to this on longer term...
I would mention here also one interface that I miss, reporting played tracks to last.fm
For me would be very nice to have this in the future. I understand there is a plug in for MPD starting version 0.15, it will be very nive to be able to set up this plug in on Bryston player (choose enable/disable, set-up username and password on settings interface)