Don't forget about BCA. They also make some quality stuff and are around the same price as the other two brands you are looking at.
But I agree, got to a shop and talk to one of the techs. They will assess what you will be doing and find a skin that works best for what you are doing.
For each company, there are multiple models of skins (G3 has 5, BCA has 1 & Black Diamond boasts 11 models) Which seems from a lot to choose from but once you know what you are doing and how often you plan on skinning, it will be easier to narrow your choice down.