Poorly designed and communicated
Reputation ranks
Ranks only ever go up; points can drop but your rank stays.
About reputation ranksYou have no idea how many modpacks I've played where progression gets completely snapped in half because JER gave inaccurate information to the pack developer about loot in chests or mob drops. No other JEI addons have this problem, and while yes, there is a command to update the information, in practice, it crashed the game and does nothing. My understanding is that even if it works, it only does ore generation graphs.
The mob drops UI looks pretty good, though it should be accessible from the mob's spawn egg.