They're small and harder to clip than I prefer. I wouldn't put them on my draws for sport climbing at my limit. I have a couple... they live on tripled dyneema runners that come out for long, moderate alpine routes where I don't see myself getting pumped at all. I would hate to have to try and clip these as the lactic acid burns my forearms apart.

They seem to be doing just fine in terms of durability.

As mentioned by brokesomeribs, the Ange S is small. Petzl's site has a video on how to clip it. In short, using one's middle finger to hold the Ange steady is not very effective. Whether one can (or wants to) adjust to the proposed "thumb" technique depends on several factors. On the positive side, the Ange S is light and it's snag-free--more so than any other wire-gate biner, including the WC Helium in my opinion. The Helium is great, and of course it's much larger than the Ange S. But the nose of the Ange is smoother than the Helium's.

Also, not specific to the biner itself, the rubber retainer at the rope-end biner of the Ange quickdraws is better than that of the Helium quickdraws.

If you don't mind the cost and the fact that it comes in only two colors, the Ange S is also a good cam-racking biner.

I've used the smaller version of Ange S biners and I kind of like them, including their clipping feel. Compared to other small carabiners, which typically are nosed, it's a lot better. In case of full sized version, I would probably go with some other one, Wild Country Helium and Mammut Bionic Wire Safe Gate being the most likely alternatives. I'd also like to try the new DMM Alpha Trad biner (see the comparison here: http://www.tribevine.com/products?open=true&ids=4332,4337,5035,6419,4327,4328&title=Non-Locking).