Welcome back, I'd say that the end game is pretty good, and yes being in a good FC can make the world of difference. I like duty roulette which opens up all the game content and rewards you with end game currency, Crystal Tower, and Coil, along with new dungeons. Needless to say I'm quite busy.

If you've been gone for a while I recommend unlocking retainer ventures (level 15 quest in the city) and the challenge log (level 15 quest in LL) for added help.