Shamelessly stealing from Crevan in this post on EJ:
So, take from that what you will. Keep in mind, Crevan ran this on a Patchwerk-style fight, which is where we would be more likely to see energy issues (due to not changing targets, and therefore not having any idle phases). It looks to me that 4P is very low on the list, but 2P did the best overall.
no tier 118114
I think if you're ever encountering energy problems, 4P may be helpful for you. I personally don't find it as helpful (keeping in mind I am 494, with just barely 4K haste and 30% crit) with the change to Ascension, as there are times that it causes me to put off using my Fists of Fury. But I've found 2P to be helpful - less hurt if I make a mistake on FoF's usage, and the lower CD.
Also, you should run some numbers to see if maybe you can adjust how you use FoF. It's not always a DPS loss if you energy cap during it - I found that (provided I received all ticks) casting it at <89 energy was not a true DPS loss for me (keeping in mind the math is relatively new, so I may have run my numbers wrong and it may still have been a loss - it's hard to tell).