When faced with the choice between unverifiable secret work or highly visible work (open source, name brand employer, etc.), be sure your compensation expectations are weighted to match the future marketability of the experience you stand to gain on the job.
It would be nice if prospective employers could just know that you are out there and that you are competent. Realistically they are going to prefer the safe bet presented by a known-good contributor with an impressive public portfolio.
Edit: rephrased to clarify my work sorting heuristic.