Coil springs are very simple by nature. Some v springs, with legs, arms, hooks and rollers attached or as part of their original design are very complex machines. I know it's a bit of an over statement that you reach into a bin for a coil spring and open up the entire shop for some v springs. But not by much. There are just no off the shelf v springs to speak of, so replacing them is a more major task by nature. The plus is that both types are extremely durable so replacing them is a very rare thing. And some designs just can not be done with coil springs. For those a v spring and that complete shop are a must. Also someone like Dewey to make it. Good thread as long as we are dealing with guns.