Calling the UDOO a RaspberryPi killer is not exactly true especially when one looks at the price difference. Having said that, the RaspberryPi is in a bit of a different Category. The RaspberryPi is probably more comparable to the PCDuino or the Beaglebone.
The UDOO is more comparable to a combination of the beagleboard XM / Pandaboard ES + Arduino Due or the Wandboard + Arduino Due
The 1/1.2GHZ IMX.6 dual/quad core proessor with vivante GPU + 1GB of RAM provides at least 2X the processing power of the 700MHz ARM11 on the raspberry Pi. It really is a different class of CPU.
Compared to its competition
Beagleboard XM + Arduino Due = 130+ 50 = 180
Wandboard Duo + Arduino Due = 100 + 50 = 150
Pandaboard ES + Arduino Due = 160 + 50 = 210.
So $109/129 for the UDOO is not a bad ideal, especially that it has things like a SATA connector. It would've been nice if the board brought out some of the IMX6 I/O pins in addition to the Arduino Due IO, but I doubt this will happen.