By the number of thumb releases for sale on AT classifieds it must be a slow journey to find the right one.
People like to believe that the latest and greatest will improve their shooting. A tension release is the easiest to learn. After that a hinge, then thumb button, then wrist strap index finger.
Also, executing a shot properly is easier with a release that has a pretty heavy weight and no perceptible movement in the trigger.
Good archers can execute with any quality release regardless of the style. When learning, it is nice to have a tension, hinge, and thumb button that work together as a set with the same grip, head length, etc. I have good luck with the nock on releases all shooting the same point of impact (2 smooth, nock2it, and silverback). There are others that will work similarly.
Once you get the hang of things, it is pretty handy to hunt with a wrist strap release. You want something that can set tension and travel independently, so you can set tension heavy and travel to as near zero as possible. It is also the hardest set-up to keep from punching. The reason most people get target panic is they start with an index finger release and think they are going to shoot a bow like a rifle. After that they have to get rid of bad habits and relearn.
That is where you see the buying and selling of releases happen. In all honesty, I have had very few quality releases. If you can set the travel to zero and the trigger tension heavy, you can learn to shoot it in a few hundred shots. People think the reason they can't shoot is because they don't have the magic release. In reality it is about the technique and level of practice.
Edit to add: I do recommend buying off the classifieds here or AT. It will save you a pretty penny if you end up not liking something.