my last comment may have been too focused on availability, so let me clarify why i always choose the original pressing.
when a band goes into the studio with a producer and an engineer they all work together to create the final recording that we listen to. they give it a specific sound, a specific mastering, and it's all very intentional. i find a lot of reissues are also re-mastered, and that it takes away from what the artists intended in the first place.
now, there are a few exceptions where the original artist or producer does the re-master and it's just as good or better, but i don't think this applies to most reissues today.
i'd rather listen to the music as it was intended to be heard, rather than a version that might sound clearer, or crisper, but in the end doesn't live up to the artistic vision of the original producer.
just IMHO ..