rocky:
MPD stand for "Music Player Dameon". Its just the software that plays back the music. Bryston has been making improvements over the years and to my ears, the latest version smokes the one in Loony Loones. So it's worth it to upgrade to MM just for that.
Forget trying to figure out how to install MM from forum posts!
Just call Chris any workday and he will get you there step by step. I think he spent 3 hours on the phone with me at one sitting. If you are totally a computer illiterate, have Bryston send you a new flashcard (with MM pre-installed). They did that for me free. Then all you have to do is remove the cover screws and swap the flash drive cards, and re-boot the system.
I don't stream radio and I am not internet connected. I too was concerned about complexity. MM is actually better than LL, but it takes longer to boot up from a cold start. The sound quality was the thing that convinced me to stay with MM. I had LL on another flashcard and could go back and forth to compare SQ. I even had to ask Chris about the SQ in MM and he told me others have also noticed the improvements. So if you can get it installed, you will be pleased.
Depending on your version of LL, MM cures a number of bugs. In my LL version, the song pointer would freeze while playing songs. I would have to "refresh" my browser screen to update the screen, which would wipe out my displayed file structure on the right. MM will use Firefox browser where LL would only use Google Chrome. MM adds a new "Artist" view, but I never use this (although its pretty cool and will display all songs from a particular artist, even if they span multiple albums and "best of multi artist" albums like sound tracks).