The transformation is where things start to differ: Armada Hotshot's legs are formed from the cab, Universe Hotshot's fold down from under the body behind the helicopter. The cab then folds down to form the back and the arms unpeg from the side of the cab.
Robot mode gains bending elbows and looses the bending knees. Unfortunately a host of other problems are introduced - the feet aren't that big and the body is weighted down by the body of the Helicopter forming a backpack. So standing Jolt up is nigh on impossible ! Then there's the tail, now positioned to the front of the robot between the legs. Oh dear. The helicopter blades can still be raised up in this mode to form a helipack above the head but it brings the rest of the back with it.
So - OK Helicopter mode but poor robot which is worse than the original. Stick with what you know.