The mongoose is my favorite.
It sucks, but I love it because its so satisfying when the passenger gets a kill with the shotgun. I love taking someone around while they have a rocket launcher too. My favorite thing to do with the mongoose (though noones ever willing to try for fear of death) is to have a sniper rifle on me, drive my passenger to the other sniper rifle, then take him/her somewhere with good visibility of important areas and take myself somewhere else that can cover him/her and also take out the enemies.
I have CDO, its like OCD, but all of the letters are in alphabetical order like they should be. 8)