How does it play? Pretty much like any other harmonica. Because there is a mouthpiece that puts your lips farther from the reeds, it might take you a day or so to adjust your embouchure in order to hit all of the deep bends precisely, but as you can tell from the demonstration videos it’s a perfectly playable instrument of professional quality.
In terms of tone, it works similarly to an electric guitar. Keep the volume controls on the Harmonicaster and amp at moderate levels and you have a nice clean tone. Turn things up and the tone starts getting more distorted and greasy.
In terms of volume, you don’t have to blow hard to play loudly.
Here is Carl Caballero of Detroit’s Boa Constrictors demonstrating just some of the Harmonicaster’s potential: