My 2 cents on CC vs. EQ:
Pinsir usually wants to come out on something it can force out for a free +2 on the switch. That means TTar dies to EQ even if it comes in safely. As for Skarm, the tiny bit of extra damage from +2 CC (It only does 10% more than Return. No, really.) means nothing because Skarm can then OHKO MPinsir with Brave Bird thanks to that -1 defense. Frankly Skarm should be completely dealt with before ever even considering starting a MPinsir sweep. Also, +2 Return OHKOs Air Balloon Excadrill, and Mega Gyarados dies to Return even at +1.
So the only OHKOs MPinsir really loses by running EQ over CC are on PhDef Ferro (+2 Return OHKOs SpDef) and SpDef Rotom-W (even +2 CC won't OHKO PhDef, in fact it struggles to do 75%, and +2 Return 2HKOs anyway. In return, PhDef and SpDef Rotom can't OHKO with Volt Switch until the defense drop from CC). Incidentally, if Pinsir really wants to kill PhDef Rotom-W, the only way to do it is for it to run Mold Breaker + EQ, get an SD on the switch, and kill Rotom before mega evolving. Not that MB is necessarily a good choice just for that; I'm just pointing out if Pinsir wants to OHKO PhDef Rotom, EQ is the only way to do it.
On the other hand, Mega Mawile is not OHKOd by +2 CC, but is OHKOd by even +1 EQ. +0 EQ of course OHKOs Heatran (just like +0 CC OHKOs TTar). Not to mention, MPinsir gets to kill everything else it would use CC for except SpDef Rotom-W and PhDef Ferrothorn without worrying about the defense drop which renders him more and more vulnerable to revenging in general but especially priority revenging such as from Sucker Punch. Being guaranteed to be able to tank a sucker punch from Bisharp because he's at +0 rather than -1 or -2 defenses, for example, removes the need for Quick Attack vs. EQ/CC mind games.
So in summary, by running CC, MPinsir gets the ability to OHKO 1) Tyranitar at +0, 2) Physically Defensive Ferrothorn at +2, 3) Specially Defensive/Bulky Rotom at +2.
By running EQ, MPinsir gets the ability to OHKO 1) Heatran at +0, 2) Heatran, TTar, and Bisharp without def drops, 3) Mega Mawile even at +1 (CC won't OHKO until +3).
All other things are essentially the same. IMO, EQ has enough merits to make it at the very least a genuine tradeoff.
Concerning Pinsir's ability, I find Hyper Cutter to be almost always the best choice. The ability to block Lando-T's intimidate as it switches in and then get off an SD after Pinsir Mega Evolves has proved invaluable to me numerous times especially since Lando-T goes down to +2 Return but not +1. The +1 from Moxie, ehh, it's too situational and I hardly ever am able to set myself up for it. Besides, like I said, instead of sending it on on something weak I can kill, I'd rather just get it in on something I can scare out for a free +2. Not to mention, Pinsir can take advantage of Hyper Cutter by Mega Evolving as the intimidator switches in, but it can't take advantage of Moxie without waiting until the new mon is already in before evolving, meaning it can more easily be outsped.
