My best setup with the Skorpion is to use long barrel and extended mags. It's a bullet hog and it's accuracy isn't that great unless the enemy is close. If you are trying to hit someone beyond near medium range then you need to burst fire it or you will spend almost an entire mag just trying to get the kill. All that being said, if you stick to close quarters type gunfights, it's a really good gun. You just have to play to it's strengths. I generally run it with Ghost, Toughness, and Extreme Conditioning. This lets me get in close with it which is the only way to be really successful.
The Skorpian is one of those guns that feels OP when you die from it but it's not really OP.
I did the Gold challenges for it last week and it felt inconsistent. Some matches it felt like the second coming of the Ak74u and some matches it's like "OH MY ******* GOD I UNLOADED MY WHOLE CLIP INTO THIS MOTHER****** AND HE'S STILL ALIVE !!! GOD DAMN IT RELOAD QUICKER YOU PIECE OF **** GUN!!!!"