The Mammut Contact Dyneema slings were some of the first skinny climbing slings to appear. When I first saw them I reacted as many people do: "Really, those are full strength?" But yes, they are full strength. And thanks to a patented "Contact stitching method" they are maybe the thinnest and lightest slings available.
Overall, these are our top choice for Sierra routes and alpine climbs because they are so light. They performed well in our tests except for the durability test where we found them lacking when compared to the similar Mammut Crocodile. For big walls or heavy use on trad climbs, go with a more durable 10mm sling like Mammut Crocodile Sling or the Black Diamond Dynex Runner. The super skinny design also makes this sling difficult to untie once a knot is weighted. It seems that its greatest strength (super skinniness) is also the source of its greatest weaknesses (durability, knot untying). For overall utility, durability and price, it's hard to beat the regular old 9/16 webbing. But if you want the lightest sling with the least bulk, this is it.