I have been playing around with thumb releases and hinge releases for a couple of years now. The accuracy potential is phenomenal. As previously mentioned, proper technique and form are paramount. If I were to rate the different release types, I would rate them as most accurate: 1) hinge release, 2) thumb release 3) wrist release and 4) fingers. All can be shot with great accuracy.
If I were to rate the different releases for hunting, I would rate them just the opposite: 1) fingers or wrist, 2) thumb and 3) hinge. For me, being able to control the exact moment of arrow release when hunting is paramount. Idiot Proof Archery is a good read. Bernie does a good job of explaining release types and styles. Another great read is <padgettarchery.com.> He explains several release engines, some of which can be applied to thumb releases.