I've started playing with it and it's fun, but like other experiments in computer-generated music -- including those of some of my students; I've had two develop functional, but very limited, music generators -- it sounds rather one-dimensional. In other words, the music is superficially appealing, but lacks any depth, direction, or (for lack of a better description) melodic or emotional message.
By way of analogy, if it were a poetry generator, it would be writing superficial, robotic (exactly!) poems like, "I am I am I am I am you are you are you are us are you are us are you are we are we are we are you."
Sometimes, it seems to gets the register of instruments wrong, like a bass will dip jarringly far (what is that low string, an E-what-the-****?), song endings feel like it's given up hope rather than finished, and occasionally it sounds out of tune though it probably isn't.
Of course, maybe that's because I'm using "Simple" rather than "Pro" mode. Have to try the latter, later.