The true credit goes to my friend for finding this and pointing it out to me, but since he doesn't use this site, consider me posting this for him.
Okay, today he joined my Sethekk Halls group to help me out, we had a tankadin who gave give him Greater Blessing of Kings. Well, after we finished, my friend left the group, and my group and I rolled on the loot.
Later that night, my friend switched back to his main, and noticed he still had the Greater Blessing of Kings on, and active(+10% stats). He invited me to a group, and the buff was in fact on.
For those who don't understand why I point this out, in a recent patch, Blizzard made it so that raid buffs(basicly the big version of smaller buffs, ie; Gift of the Wild, Prayer of Fortitude, Greater blessings) are removed when the caster is no longer in the group.
SO! In short;
You seem to keep the buffs from Paladins when YOU are the one who left the group, if the paladin leaves, then you lose the buff. This could probably be used for Soulstones too, and similare buffs. But since it's late, I'm not going to test right now.
Hope yall enjoy! =)