David,
The jSax looks really good. I have some nephews and nieces and have these questions especially with a beginner in mind. But, to be honest , I'm asking for me too

Compared to a regular sax, does the jSax have
All 12 chromatic tones, and similar range to a sax.?
Is it easier to play in tune and by how much?
Is it is easier to blow and by how much?
Is it easier to physically play the notes?