I shoot a Hot Shot Vapor 3 and could not be happier with it. For a lower price range thumb release I am not sure you could ask for more. It has great adjustability, nice finish, and a really good warranty from Hot Shot. The only issue I have had with it is that I am a sweaty guy and the finish is a bit slick. So I just got stick on grip tape from home depot for $5 and cut little strips to place on the areas where your fingers make contact. However, if you aren't a sweaty person this probably wont me an issue for you.
Also, if you decide you don't want it, let me know please. I have been looking for another at a reasonable price for my wife.
FYI, use lock tight or similar on the trigger adjust screw once you have it placed. They can and will float in place. This is nothing against Hot Shot though as I understand that most releases with similar trigger travel screws will float in and out with the vibration from operation. I just put one drop of super glue on the side of the threads. Easy to remove if needed and keeps it from moving.