When shooting backtension releases, you should realize that after time you can learn to force them to go off when you want, which defeats the purpose of a surprise release. If you try to hunt with one, you will find that with some shots, you have to force them to go off, or you will miss the opportunity.

You can also learn a surprise release with a more traditional index finger trigger release. As a hunter, I've found these releases to work better for the various senerios that typically occur while hunting.