A Question: What makes for Good Vinyl?

To answer this question properly, please provide context.  Are you asking a question about the material itself, or something about the use of the material in the manufacturing process, or about the performance characteristics of the material as applied to records, or what?

For example, what makes RUSH albums sound so great?  Does it have something to do with the pressing? Or is it mainly the recording, mixing and mastering?

And as a follow up which albums/recordings are the best/worth having?

I can give you some thoughts, hopefully others will contribute more.  The key to the sound of a record is how it is mastered.  If you check your Rush records chances are that at least some of them will disclose in the fine print on the back who the mastering engineer is.  Since you like the sound of Rush's records it is probable that you would like the sound of other records mastered by the same mastering engineer.  Another thing to consider is the record company.  Most record companies have a "sound" and you are likely to find that you like other record releases from that same company.  For example, I like Blue Note records and most recently ones mastered by Kevin Gray.  Hope that helps.

the studio engineer, the recording, the label, the pressing, the number of copies from the master... since it's such an analog process, every participants' mood in this chain, if they had a hangover from the night before, etc...

RUSH??? OMG....