A lid spring counter-balance helps prevent brick damage. One of the causes of lid brick damage at the hinge area is the operator pulling down on the lid before a locking device has fully disengaged. The spring counter-balance prevents that type of damage, because there is no locking support arm.
The spring counter-balance also distributes the weight of the lid better on the kiln. This eliminates some of the wall flex that the weight of an open lid causes.
If you have a kiln with the spring counter-balance, a caution: Do not let go of the lid when the lid is almost all the way open. If the kiln is tall and you have difficulty reaching the center lid handle when the lid is open, use a side lid handle. If you let go of the lid too soon, the force of the spring can damage the lid.
By the way, you can install a spring counter-balance on an existing kiln of any brand. An alternative would be to install a pully system with a counter-weight.