It's impressive, but keep in mind we're comparing an embedded system to general-purpose OS+UI here. This thing is booting a probably hardware-customized Linux kernel, a trimmed-down Qt runtime, and directly into a very bare app UI (almost a mockup, except for the video screen and one button).

That's quite an achievement in itself, but I wouldn't expect the same with an N900 or N9 booting a larger kernel (with hardware detection etc.) with plenty of services to set up (telephony etc.) and a complete system UI like Fremantle or Meego on top of GTK or Qt.