In reply to Oceanic: I tend to use what ever is to hand. Whether it be a quickdraw, or a spare snap/screw gate krab.
Most of my slings are on screwgates but 1 or 2 are on snap gates. I tend to use at least one screwgate on the gear, but my rule of thumb is to always use a screwgate when the rope is running through the krab, or when i need to attach the rope via a clove hitch multiple times etc.
Although, winter wise, screwgates are prone to freezing shut, so in that case, i use wiregates but doubled up. I.e gates open in opposite directions or one gate up, the other down.