i beat Path of Pain a while before P5.
Path of Pain took a while to beat due to just how precise each movement needs to be. You have to be fast and have a good reaction time. I healed a LOT, but I eventually beat it.
PoP is easier than P5. P5 is every single boss in the game in a row, with only a few breaks. Oh, and all of the boss arenas are in their Ascended form. If you die at all during P5 OR Path of Pain, you have to do everything you did before you died, but AGAIN.
Of course, that also goes for the other Pantheons.