The principal values of things like the Jepsen reports is to the community of potential users/purchasers.

I agree with GP, that vendors should be somehow required or very strongly encouraged to participate in such audits. Not because they want to (as you say, most wouldn't like their dirty laundry aired thus), but because consumers deserve to know. U.S. government software groups don't like FISMA/RMF audits either, but they have to do them anyway.