The Gorilla is a very useful unit if used correctly.
YOu need first-person to appreciate it though. It seems like AI control makes th egorillla suck. The AI gets very wonky

and you stumble around and get torn apart ny a hoard of small units.
Use the tab key to use just the rockts. Send smaller units ahead to fight and use the superior range of the rockets to help. If thing get hairy resort to the ground pound.
The same may be said, I suppose, of the Goliath. That too sucks becuase it moves slow but the weapon is awsome. Keep one handy at camp, pput him in the back with a clear line of fire and set to high initiative/stand ground. Their cylce time is slow but the weapon is devastating.
I only use these if captured by a judas, becuase they are not worth the minerals used to make them.