Loongson is less complex than a modern x86 cpu.
And sure I think the Loongson3C is nice ;)
The only problem right now is: I can not buy one.
Finally you can order the Lemote Yeelong 8133 with Loongson 3A CPU in Europe (source)
It is quite expensive though.
Michael, some benches of it? Maybe you could get a review unit, being the linux bench site and all ;)
I have the Yeeloong Lemote, it is a nice piece of hardware although the battery lasts no more than 2 hours (which is still pretty good).
About the openness of the platform, unfortunately two elements remain non-free: 1. the embedded controller firmware (which manages buttons, power, ... I think it's a 8051), and 2. the firmware inside the HDD itself (which depends on your brand. usually it's a small ARM uC). It's not really a big deal anyway, but afaik there is no completely free hardware platform at the moment, except completely FPGA-based ones like Milkymist - and even then you need proprietary FPGA tool to recompile the bitstream.