Half-Speed and other Audiophile grade vinyl is worth it if the original record was a well engineered recording. I have some rock and jazz; like Steely Dan's "Aja" or John Klemmer's "Touch" on half-speed master vinyl that will make you weep at how much better it makes an already outstanding record sound.
I also have a few master versions that just reveal a poorly recorded original session. Its all about the source, but unfortunately you can only discern the difference between good and just OK by trying it out. There may be master reviews on Discogs or some other vinyl source (any body know a good reference source for master recording reviews? Not just some deletant comments, like my opinion).
In short, generally I find if the original version was great to listen to; then the half-speed or master recording will be an even better version and worth the premium.
I also have a few master versions that just reveal a poorly recorded original session. Its all about the source, but unfortunately you can only discern the difference between good and just OK by trying it out. There may be master reviews on Discogs or some other vinyl source (any body know a good reference source for master recording reviews? Not just some deletant comments, like my opinion).
In short, generally I find if the original version was great to listen to; then the half-speed or master recording will be an even better version and worth the premium.