The video quality on the two releases is near enough to not matter to me after checking them both side by side for ~8 mins, below is what I found during that time. Can upload screens if anybody wants.
Plus for G_P is that they had the kanji for the songs during karaoke. I didn't find any others.
Plus for FLF & L-E is that they have more sub tracks to choose between depending on what one wants. Karaoke, notes or just normal subs. At ~2 min mark they put subs up for what the crew was saying. (Which for some reason MPC HC didn't capture, even though it captured the other subs.) They used the miclone term instead of micron.
Something that I am not sure is a plus or not is that G_P used the romaji of what was sung while FLF used the actual English word. For example, HAATO vs HEART and RABUSAIN vs LOVE SIGN. There was also a few other instances of differences where which side that came out ahead wasn't clear. G_P felt more literal while FLF felt more like it captured the meaning in a natural way.
http://forums.animesuki.com/showthread.php?t=22628 also had a minor discussion about this.