To put taste of the listener aside, in his mind they are equal in quality and successful in terms of what he wanted to do. A fine axiom of Bill's that bears repeating: "everything I could do was ALL I could do."
I always approach those recordings with that in mind. But I wouldn't disagree that some are more quickly evocative or strike certain emotional chords with more immediacy (to me) than others. The Firehouse 12 set for one - I was just immediately in love with it. Contra Thoughts, which I don't listen to quite as often. It had some problems with the levels/balance on the production end, though with the volume cranked to 12 or 1 o'clock, I don't notice it. Obviously that doesn't reflect the intent/validity of the contents, rather the label's quality control.
So yeah, there are multiple sides to the story as well as how one processes the work, but he always did what he sought out to do with recordings that were intended for release. Those that were not initially intended for release but have been or will be uncovered are going to be more of a window into the process, but with intent intact. Obviously I can't totally speak for Bill, but I can try to give you a window into his thoughts about these very matters, resulting from many hours of conversation.