The boards arrive and preliminary inspection shows all boards seem viable, and the alignment seems clean—but I haven’t done complete circuit/lead testing yet. I have begun soldering pieces in, though, and am happy to report that the vendors completely failed to screw up (for the ironically impaired, that means “they done good”).
Note that if you want to order 10 or more of each board, you can just skip this entire section. Most PCB fabs are very cost-effective at that point. My analysis is only for people trying to minimize their costs for very small (2–3) quantities.
You want to simultaneously order spares (in case you screw up during assembly) yet not buy too much (in case you get a bad batch). Several of these prices might be intro rates or specials and may change in the future. Ultimately I can’t prove these are the one true path of PCB. But for small quantity hobby ordering for picosatellites, I think these are viable choices.