I have used them many times with mixed results.
If you are going after panfish, it almost isn't worth it. The thing triggers so hard that it usually rips the hook right out of the mouth of the fish. The speedhook still continues to fish, but sometimes they come back and sometimes they don't. Sometimes the bait is launched, and you are sitting with just a hook. Make sure you really secure your bait on the hook.
With bigger fish, it works pretty good. The one thing I have learned is to set the trip so it takes some effort to trigger it, not a ton, but some. Don't set them on a hair trigger. Just simple water movement can set them off. Again it still is fishing for you, but you lost the idea of this being a trap of sorts, and maybe your bait as well. I set mine so that I can handle it and not worry about it tripping on me. A good rule that I go by is if I am handling it like a set mouse trap, chances are I have it set to light.
They come with a little adjusting tool to bend the trigger to give you different degrees of force it takes to trip the trap. It is nothing more than a roll pin really, but it works and don't loose it, because after you catch something, you may have to adjust the trigger again depending on what the fish does and how hard it fights. They can bend your trigger and it will need to be bent back. Try and get the military ones with the dehydrated bait. That bait believe it or not, does work, at least it has for me.
Something you may want to do as soon as you get them, is to change the line on them. The main line is pretty tough stuff, but I changed it out anyway along with the line on the hook. I had one break on me. I am not really sure what happened, but when I came back, the line for the hook was snapped and the hook was gone. I think the monofliament line might have been old, and what ever was caught, just broke the line. Now I use 50lbs. main line and 20lbs. for the hook. Both are braided line.
I have never used them for animals. I just don't have the heart to do that if it isn't a survival situation, but I feel very confident in doing so if need be. The only thing I would do is change the braided line to a wire leader as I think an animal may be able to chew through the braided line. It is easy to swap out.
Keep an eye out on ebay. I bought 20 brand new military ones for just over $3 each shipped.
