My friend and I both levelled a Jedi Guardian and Sage from 1-50 side-by-side throughout the whole of their career (easier to do with rl m8's). Currently we're sitting at just under Social rank 6, we've still got a bunch of the old Bonus series quests to go on several planets that may up it some more but yeah its a proper grind otherwise.
Still its nice to have the 'Party Time' title as you don't see it around barely at all ^^