If I remember correctly, the Galileo is a hybrid Linux-Arduino board similar to the Arduino YŁN and Tre (though x86-based rather than ARM-based).
When you do get one, it'd be interesting to see how the X1000 compares to the CPU portion of the BeagleBone Black, which has two non-AVR on-die microcontrollers (called Programmable Realtime Units).
Yes, the Galileo is a Linux based arduino, and it isn't really meant to run the same sort of tasks that you do with beaglebone. Off the top of my head, I'd say the only platforms you can compare it to (that PTS will actually run on) are the arduino tre, either of the beaglebones, raspberry pi, and probably some FPGA platform. Everything else isn't worth comparing. The Galileo is just a really powerful microcontroller.
Ugh. In that case, I might as well just get an an Arduino YŁN or hang a cheap Chinese Arduino clone off one of the USB ports of a Raspberry Pi and write my own wire protocol.
Yep. The Arduino Tre will also be a sane solution, when it comes out.
The Galileo development board also says explicitly that it cannot be powered via USB, as it draws too much power. I am really hoping that by the time the Edison is out, Intel will have gotten their act together.