1. Aneubis is right about the armor. I never thought I see Rooster post incorrect info.
It doens't repair the shield belt cause you can lose the shield belt and still retain some normal armor.
2. Goo doesn't always stop shock balls. I think the way this works is that the first person to shoot is the one that gets stopped. I've fired shock balls through just about everything, goo, flak shells, rockets, etc. , and not only does it keep travelling but you can combo it afterwards.
3. Just so you know the goo gun can do up to 800 damage on a full load with a direct hit. That will kill you. A full 6 hit rocket cluster will do about 450 I think(which will still kill you regardless of armor). Problem with the rockets was already stated. Sometimes the first rocket will blow you away from the other rocket's blasts(even on a tight circle).
4. If you're running away from someone and throw the goo at the ceiling it usually works better than the ground cause they can't usually jump over it as easily.
5. Also if you drop goo and switch to another weapon, like RL or shock you can blow your goo up on purpose to get the added effect of the goo AND your rockets/shock. This works against people using goo on YOU as well.
Oh and it WILL drip off the ceiling if it barely hits it(hangs down anyway).