[The Great Fumar]

HB
Nails are best, vinyl siding has elongated holes , the nails are driven through these holes but not all the way in..Its best to leave about 1/8 inch out of the wood ....that way when the temp. changes the siding can slide and not buckle...many times when staples are used they drive them to far in and the siding can't move but it still expands and so it has to buckle.
NOW having said that , you can have to same problem with nails if they are driven in to far. But its not as common with nails as they are normally nailed by hand instead of a staple gun....I hope thats clear.....I personally have never done it , BUT I DID STAY AT A HOLIDAY INN EXPRESS LAST NIGHT.