In reply to RyanOsborne:
Just from shop really, but I considered getting some of them (given I have Gridlock, Gridlock Magnetron, Edelrid Nineteen G, Rhino, DMM Oval with Quicklock gate, etc., I am quite a gear addict and like to see if these strange carabiners work).
I wasn't sold purely because if the wiregate touches the rock, that's basically the only one way to open a wiregate in an anchor system (rope/sling is less likely to open the gate, IMHO). While slider gate has a lower surface area which allows the gate to be open, it is still the same direction. Lately I have been using two opposite and opposed carabiners for crucial pieces which in theory are safer than screwgates. However, I really love Edelrid Pure Wire carabiners which I own.
On the other hand, Mammut Element screwgates are 3g heavier than Edelrid Pure Slider and they are 15 quid for 3-pack on RockRun.com (instead of 15 pounds for one Pure Slider!). Both Element and Pure carabiners are identical in teroms of size and shape.