RE: to loop or knot to loop
I started using a loop 12 years ago and not once has one broken or come untied on me.
Having said that if you tie it incorrectly it can and will come untied and you may end up punching yourself in the mouth or nose. Like anything else it must be installed proplerly and you must change it if it begins to show signs of wear.
The many benefits of a loop far outweigh the one or two negatives that some people can come up with.
They are lighter than brass nocks so you gain a tad bit of speed.
You are pulling directly behind the arrow and not below so all of the bows energy is transfered directly to the arrow in a straight line rather than having the lower part of the string instantly become slack at the release and snatching the nock end of the arrow vioently downward at the release.
They eleminate nock pinch and arrow fall off.
You can change the length of them to fine tune your anchor point to your prefered spot.
They act somewhat like a string leech and vibrate out of synch with the sting to slow the strings vibration. Certainly not as effective as a leech but they do help some.