Shiny w/ Lick for sure. Gengar's DPS is already tops, going from 14 to 15 attack isn't going to change that much. But having the extra bit of stamina might make the difference between getting off an extra Shadow Ball or not. Plus I think it's way more fun to use energy generating fast moves and try to get off as many charge moves as you can.
GamePress
Gengar power up
Guys, which Gengar I should power up? I already have one 98% max out with shadow claw, now I want max out another, I have other with shadow claw 89% 15/13/12 and one Shiny 96% with lick 14/15/14. What you guys think I should go first?