I sold both of these products for years. The sounds in the Black HR16 are different. There are very few acoustic sampled drum sounds. Most are hip hop and techno. Most of my customers prefered the HR16 (Grey). If you want great sounds, with lots of them, I would recommend the SR16 which has been out for many years now and is still made. It sells brand new for around $200.00. The number of sounds are really significantly more on the SR over the HR.
George Kaye
Kaye's Music Scene
Reseda, California