Rockchip’s stalwart RK3066 can best be described as a dual-core ARM Cortex-A9 chip with clock speeds up to 1.6 GHz.
As Liliputing's Brad Linder notes, most of the above-mentioned devices ship with Google Android as an OS, rather than Linux, as Rockchip hasn't exactly released a lot of source code for its processors.
Nevertheless, a number of developers, including one by the name of AndrewDB, have been making some significant progress porting Ubuntu 12.10 Linux to run on the UG802 (and other RK3066 devices).
Interestingly, AndrewDB managed to access the source code when the manufacturers of the bq Edison tablet released the source for the device's kernel.
Unsurprisingly, Ubuntu for the UG802 is still a work in progress as WiFi only works with a USB dongle, while the Bluetooth dongle is somewhat buggy. Then again, the UG802 version of Ubuntu already supports 1080p monitors using the integrated HDMI port, so progress is clearly being made.
Personally, I'm a big fan of such ports, as they offer users the option of running more than a single OS on Rockchip-powered devices, making the above-mentioned PCs-on-a-stick even more versatile and cost-effective than they are now.