359 Absol

Snarl falls behind Psycho Cut slightly in energy gains, but offers significantly more damage output thanks to STAB. The latter can be chosen if that slightly extra energy generation is needed. 

Dark Pulse costs the least amount of energy and benefits from STAB to provide Dark-type coverage. Payback is less desirable due to its greater energy cost. Megahorn provides Bug-type coverage and costs slightly less energy than Thunder, while the latter offers Electric-type coverage. Either can be chosen depending on what coverage would be more preferable. 

Absol is the definition of "glass cannon" in PvP, with extremely fragile bulk almost identical to that of Gengar's. Since Absol can't tank damage very well (if at all), Absol demands shields to perform well, though shields won't save it from Pokemon with strong fast move damage output like Deoxys Defense Forme or Altaria. Pokemon with emphasis on charge moves instead of fast move damage tend to be better matchups for Absol, though Absol tends to lose more often than not due to its poor bulk. Overall Absol shouldn't be used for PvP, and if it intends to compete then specific PvP formats that limit its weaknesses would be more ideal. 

Absol doesn't get any ratings for Ultra League due to its inability to consistently perform in its role as a Dark-type. Losses against Giratina-Altered, Cresselia, Armored Mewtwo, Gengar, and struggles vs Gallade despite doubly resisting its fast move makes it very hard to justify Absol compared to other meta Dark-types. Wins against Giratina-Origin, Drifblim, Slowbro and Bronzong are to be expected, but losing against several opponents even when given a typing advantage is a really hard pill to swallow. 

Absol lacks stats for Master League, with no real clean wins against the meta.