Sceptile 2nd Charged Move

I'd try Earthquake. Avoiding a need to switch and potentially trap your steel counter is a huge boon. If other grass types or mirrors give you headache you can always switch and see which move you like better.

I rolled EQ as my 2nd move but I don't think I've ever actually used it. Pinsir seems to be his PvP nemesis, so AA would probably be more useful. FC/LB is just so great in most situations

AA would be better for mirror's, but EQ would be better if you see a lot of giratina coutners; Aggron, Lucario, steelix

Ive heard good things about both sets, though have yet to use one myself

In terms of the moves themselves, AA is pretty middling in PvP, whereas Earthquake is a very strong move, which counters a lot of strong PvP pokemon. AA is faster, though.

I'd look at which move covers more of the many types that resist Grass. Earthquake hits Fire, Poison, and Steel well, whereas Aerial Ace hits Grass and Bug well. In the PvP circles I play in, there's far more Fire and Steel than Bug.

Additionally, in the Ultra league, the big heavy moves are more useful (in Great League, faster charged moves seem more effective to me), which again points to Earthquake. Finally, for UL, consider waiting for Treecko's CD, where you can get (presumably) Frenzy Plant - slower to use but does a bit more damage per energy. (Unlike most of the other CDs, Frenzy Plant is pretty close to Leaf Blade in performance, so it's not a game changer, but my gut tells me that it will fare a little better in the ultra league.)

Finally, you can't decide on a pokemon in a vacuum. Think of it as part of a 3 pokemon team. If it's paired with Flygon and Steelix, you probably don't need more earth coverage. But if paired with Lugia and Moltres, you've got the flying thing well covered.

IMO unless you're getting abused by Pinsir and other bugs, or Counter users, I'd go with Earthquake.