Just to add a bit more to the pot....though I believe they really have the potential to increase accuracy on short length bows I do not entirely believe that they are necessary on the longer ones. The reason I say this is because I have been shooting a Pro 40 Freedom for the last few months right off the string with an eliminator button and a tied-in nockset and am getting some incredible accuracy with this setup. I did not see an increase in accuracy when I used a string loop with this particular bow.

Just something to think about.