I have never really liked the metal staples for some reason but some people really like them.. Personally I only use them to fasten bare copper ground wire and thats about it. As for securing Romex, I really like those plastic staples, they seem to nail up really good regardless if its a regular piece of spruce, an old dry joist or even a knot in the wood. Also, I find that if you have to pull one out they can be removed easily with sidecutters and with minimal risk of damaging the cable..
A.D
