Choosing between Reissue and Original pressings


Reissues have been common since quite some time but these days as vinyl has picked up momentum again, there have been some very high quality reissues from labels like Classic, Analogue Productions, Speakers corner, MFSL, Boxstar etc. For any particular album how do you decide whether buy a good reissue or get a good copy of original pressing from ebay ?

For the sake of discussion lets keep out exceptions where the original pressing is too hard to get or too expensive. In most cases it is possible to buy a copy of original pressing for sane amount of money if one shops carefully on ebay but I have also found that quite a few times a high quality reissue can sound better. Whats the general thought among hardcore vinyl followers here ?
pani
Working duplicate tapes of the master are generally shipped overseas for release in other countries.

These duplicate copies were most probably made out of the original copy ? If yes then obviously they would be inferior to the original because in analog there is always loss when transferring information from one tape to another! So, probably the tape that were being used in other countries were inferior in the first place ?
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Viridian, It's ironic but it looks like vinyl will turn out to be the longest lasting medium for archiving music. With minimal efforts at storage, a vinyl record can maintain its sound quality indefinitely and even if there is some defect the problem rarely results in not being able to hear the music. The same can not be said of tape or any form of digital storage.
Whart, if you see that, then yes. You might want to read the Wikipedia page on the Heaco.http://en.wikipedia.org/wiki/Haeco-CSG

Pani, correct. That is why the country of origin is so important. ELP released their first LP in the US and the UK. The US Cotillion is quite good, but the Pink Island is much more lively...
I'm surprised that some original LP's from 40 to 50 years ago sell so cheaply for their rarity.IMO this is last chance gas to hear the best sound quality of some of them.As a consumer and audiophile I would rather pay the price for a company to come out with even a standard red book CD recorded off the best expensive state of the art TT and equipment from an original first press or promo and sell it as such like off of a half a million worth of TT and gear.Then I would like to put that recording up against what's out in today's reissues on my modest system.I believe most would be better.