I picked on of these up when I found an odd crack in my Omega Pacific Jake. The keylock nose is so much easier to use. I haven't found anything I don't like about it yet so I'll give it a five. Nice job Petzl!

The best master point biner made!

Super biner for its size. If you need a larger biner I would chose this one. I use it on trad anchors, my daisy chain, and tie in points. The only problem I have had was with it's shape. I like round shaped shafts for belaying with a reverso, the Willaims has an oval shap which is not a smooth.

This is the first locker I bought when I picked up climbing. I thought that the huge size would make it easier for me to clip and belay as a rookie. After about 4 months, I switched to a smaller carabiner (BD Mini Pearabiner), and found that it was a lot easier to work with on belay, and the reduced bulk was nice to have.
However, the keylock nose and huge basket are the perfect thing for setting up anchors. I've acquired a couple more for that purpose. My only complaint is that, within 1 month of use the screw mechanism became slow and needed to be lubricated. Overall a very good biner, and very easy to use.