Wow....how does one measure "punch" ? I think the newer psr models are equal to the G1000...maybe better in some ways. The Ketron sounds are very "live" by nature, but aslo pretty noisy. The Yamaha stuff is among the quietest out there.
As for punch......shut off the speakers, and listen to the SAME sound system. Maybe the punch comes from the external amps. Sounds like a very subjective opinion here.