Clan size doesn't help either, Iam on more than my guild online status shows. I am usually on alts after I do my PvP stuff on my main.
The 3 AP isn't bad, but I have no idea what other gems people are using at end game along with the pure AP gem. This gem might not be the best in slot (I have no idea), but I don't think it is terrible either.
Diamond AP
Amethyst heal on crit.
Ruby damage on hit.
Fourth slot seems to be the most flexible slot? Like Citrine damage on CC or the event gem.