PSoC5 is supported by GCC, the Cypress PSoC IDE just makes it easier for novices to get started. There is also a FreeRTOS port to PSoC5, so you can get into some pretty interesting stuff.

That aside, I am really glad they went with PSoC5 (ARM Cortex-M3 architecture) instead of the cheaper PSoC3 (8051 architecture). This makes it easy to prototype on the PSoC5 and then move to a more specialized Cortex when they hit performance limits.

Finally, I don't see mechanical drawings, however, I hope they spaced the parallel connectors on freeSOC n*0.1" apart. One of the frustrating things about Arduino is that the spacing on the shield connector is non-standard, so you can't simply plug it into a breadboard.