I got to use one of these last weekend when the rope got stuck in a slot canyon. I used one of these and a tiblock to ascent up 100' of rope to retrieve it. I own the BD Ascenders which I LOVE, but I also really liked this ascender too! It seams a little lighter than the BD version, and is easier to open to put on and take off the rope than the BD version because there is no "Z pattern" you have to follow. It doesn't seem as smooth to open and close though, but there was no slipping and it worked great! The Petzl and Black Diamond Acsenders are both great ascenders and are the same price, but I would probably go with the Petzle because it is about 2oz lighter per ascender than the BD ones.