Yeah... new mobile platform is a really hard thing to do - and without a designer (whom they clearly don't have), it's impossible. Nobody will use this.
So it's a full stack, and you can run apps from a variety of (Qt-based) sources on it. It also has a few phrases like
ENJOY NEW USER EXPERIENCE
ADAPTABLE USER INTERFACE
Focus on mobile devices.
FREE OS FOR YOUR PHONE
Uhh, okay? Oh, and the video shows that the phone is basically an Android clone. Great.
I can't talk about the other person, but if I'm being negative it's because this has a really hype-ey 6-minute trailer advertising nothing of interest. Rule of thumb: Your trailer should never be more than two minutes, because otherwise it's probably really damn slow, and frankly a minute is pushing it.
Why?
What drawbacks, again?