I had a black truck once and hands down the best looking and longest lasting was Meguires Deep Crystal Pure Carnuba. Its harder to apply than a paste wax but it last twice as long. It is not a cleaner so any polishing must be done before hand with some other product. The stuff is almost as hard as candle wax.
Second place was the Mothers Carnuba and cleaner. Easier to apply and cleans also but last half as long.
Dont own a black vehicle anymore and probably wont ever again.