Are Hordes or Pits the most efficient way to level paragons?

pit
+1 tier is only about 1% xp increase, so its not worth it to do slow runs.

Pits, probably the right level for best exp/hour is where you just one-shot everything without too much overkill.

I'm paragon 300 and I was doing 90's as evade. Best run solo was 54 seconds and in a group 35 seconds.