Well the sound more then makes up for any design flaws vs anything else on the market. A heavy metal Kb's doesn't necessarily translate to a better sounding unit as we can hear in may posted demos. There is not much difference in design material with the PSR/Tyros line of arrangers....plastic is plastic. Treat it right and enjoy the wonderful sound it offers. Heavy is fine for a studio setting...lightweight units just make sense for the "on the go" traveling performer in my book. Most likely a laptop/iPad, etc.. & a light weight controller KB will be all you ever need.

Carry On