I've looked at those. Check the razorcaps out http://www.razorcaps.com/home.html
As far as mechanicals go I've used the wasp for a few years and they leave a big cut (1 3/4") and are accurate. If used on a fast recurve xbow you have to use two o'rings to stop them from opening. You can practice with them by tying them up with a few wraps of dental floss. I do not know if they are the best mechanicals but they are the most conservative mechanicals. Yeah there are lots of them and there are lots of opinions and its confusing. I just picked the least radical one and use them. I have always used conservative broadheads and have never found a bad one. They always work for me. The most durable most accurate one I have used is the thunder heads. I shot one into a 45 gal drum and they through one side and half way into the other side and everything intact. Did it three times but the last time it lost all the blades and did a bit of damage to the shaft of the broadhead but the tip was still perfect. Problem is I haven't done that to anyother head! Did it just for fun.