I have one and love it. Saves on the string. I put one on my AR because of the peep sight I have. The peep has no rubber tube and was having problems with it not ligning up every time I drew back. The loop makes it perfect every time and still do not have to worrie about the rubber tube breaking.

As for speed I have been told it will reduce it a little because you are shortening your draw a little bit. But then again you are loosing the weight of the nocks. Who knows? Who cares? Its not enough to notice by the average hunter.

I like it, I use it.