I think it completely depends on the horse and the rider, whichever works best for them. Personally when generally jumping I just go with the automatic release, but sometimes in a specific exercise like gymnastics and bounces I like to give a bigger relese and have the rein quite loose so that the horse has to figure out it itself.
Hello Gaia, I like this article about crest release vs automatic release: http://www.successful-horse-training-and-care.com/horse-jumping-release.html
It says that crest release can be great but you have to do it right if you don't want to interfere your horse's movements.
Personally, I think that when you begin and you don't have a perfect hand, a well made crest release is great, but once you have some experience, automatic release is better especially if you have to ride technical courses at higher heights 🙂