While I like the idea of having an Arduino compatible board running Linux to do some more advanced projects, I don't understand what drove Intel to force this board to be Arduino compatible. The Quark processor is not designed for this sort of stuff as it has neither a sufficient number of GPIO pins nor any ADCs. It sure has a lot of interfaces (SPI, I2C, PCI-E, SD-Card, Serial etc.), but it lacks the things that are useful for a hacker project.
So they had to include a separate GPIO extender chip (over a slow I2C interconnect) as well as an separate ADC. The Quark SoC has some 15 GPIO Pins, the extender another 40. But of those 55 Pins only 20 GPIO pins are actually available on the Arduino shield pins -- the rest is used for all the Muxes to switch pins between the ADC, the GPIO Extender and the Quark SoC to emulate the flexibility of the Arduino AVR processor.
While I haven't looked at the actual PCB schematic, I think the board layout is also strange. The ADC is on the opposite side from the analog input pins, meaning that all analog signals have to travel a long distance in the vicinity of some high speed digital signals. And the GPIO Extender Chip is on the opposite corner from all the digital output pins.
This, together with the BGA devices (SoC, RAM), seem to indicate that this is at least an 6 layer board which will make it hard to clone this design -- something that IMHO has contributed to the success of the Arduino. The Schematic for this board has 27 pages compared to the single page of the Arduino Uno
It seems that this Board is designed more as a competitor to the Raspberry Pi than to the Arduino, both in price and in features.The Arduino compatibility is just some marketing thing which makes the board overly complex and more expensive than it needs to be.
But hey, it sure must be fun to employ a few million transistors and a full blown operating system to run the Arduino Blink demo :-)