Yes. It is exactly the same. The co-op players pause, you game pauses. If someone uses cheats it warns you. If you start a mission or activity it asks the other to confirm start. Also the story will be the same for each and will be with there character like SR3. The game is 100% the same as SR3 in co op terms. Just in a different city (stillwater from the first SR) and has a few other things, and it introduces shaundi and pierce for the first time.
Ive got all DLC, and i have a preorder code. So, if you want to play with me on PSN, add me: ccrogers15.
THANKS VOLITION FOR THE AWESOME GAME.