Hey,
good to see people are interested in this power meter + crankset as well. Unfortunately, I'm still waiting for my frame and the remaining parts to build my new bike, so I’ll only be able to review/test the power meter at the end of December or the beginning of January. Sorry about that.
I just checked on Google real quick — there’s some more/new information about the ArcRayo, but still no real reviews. Besides that, there are a few other new cheap power meter brands popping up right now like Thinkrider, Leoseek, Geoid, etc. Those might be good alternatives as well.