Out of curiosity, why the interest in these re-issues? I love these albums as much as the next guy--Eternal Idol through Tyr are god tier stuff. I don't see any reason to switch versions, though. And for my ears the originals are likely to sound much better. In me experience remasters mostly just sound louder and a bit punchier on modern, digital equipment. That's not to say bad or anything, the Priest remasters were actually pretty good, but I think I'd still go for the older versions, myself.
Is there some other angle I'm overlooking?