I like silver for the lower, because I live in AZ. When left in the car, black guns get too hot to touch, while silver guns don't. My Springfield Compact is at Robar right now, getting the lower done in NP3, just for that reason -- I burned my hand on the black frame, so I'm making it silver.
The other thing I like about NP3 is that it will run without lube. Sometimes oils and greases evaporate or dry up.