Phoronix has also done some early benchmarking on a test system Raptor gave them access to. This is notable because this means the damn thing actually exists. Although OpenBenchmarking calls it "57 cores," that's probably an artifact of SMT (my POWER6 has two cores and two threads per core, so AIX thinks it has four logical cores; my bet is that this is an 8-core system and POWER8 has eight threads per core, with some reserved for the kernel, hence "57"). Raptor has published their own set of benchmarks, but they tested against a Sandy Bridge Xeon and an AMD Opteron 6328, so I'm not sure how useful that comparison is; the Phoronix tests are against more current competitors, which I think is a fairer fight. Although they reported only three tests in that article, on the two tests where the Talos was on equal footing with the other systems (i.e., had access to the same acceleration or there weren't x86-specific optimized paths) it was nearly neck and neck with the top-ranked Xeon and Haswell i7s -- and remember you get the CPU and the motherboard for that $3K. Performance will only get better as the various Linux distros improve their support for the POWER8's capabilities. You can read some other interesting tidbits in the discussion thread.
So, again, if you're at all interested, please put in your (non-binding but do be serious) interest. Rumour has it their threshold is 2,000 units for a production run.