I'm not counting Scizor since it's from a one-off trainer that I'm pretty sure doesn't even have a name. You can't gauge powerlevels by using someone the writers don't care for us to know about.
Clawitzer is the only example I'd give, but as I said: almost every major battle. We'd need more then just a weakened shrimp to say where it stands.
We'd also need it to go up against something other than a Mega, and especially Megas created specifically to go toe to toe with its super form. Somehow, though, I don't see us getting that. Then again, base Greninja did put up a decent fight at first against Megazard X. Oh, well. I'd still put it up there with the likes of every other regional ace.