I have played both expansion boards. The Piano board is the best bargain. The Jazz Choir on the the Studio essentials board wasn't that impressive. To my ears, listening through AKG headphones, the new stereo grand piano on the first board was one of the best I've heard. It seems they have set up the filters and touch response for the Triton Pro X's weighted keyboard. There seemed to be a bit too much 'response' in the sound, but other than that, it's the best ROM board around.