Choosing between Reissue and Original pressings

With some luck it can be a view in an era which will never came back. 50 years later we discover, that the Equipment and Brain created something which is unique:
Atmosphere
The impression to be a part of that recording session. When one or the other reader wants to change the normal way of spending and spending to get different results but not better ones (from the feeling) do yourself a favor:
Buy a 2. Hand Lyra Dorian / Helikon mono cartridge, look for your favorite record in original mono pressing and listen. But you need an Arm with adjustable VTA...
It can give a fascination and sonic pleasure which is special.

Pressings are really a case by case thing in my experience. As such, SH Forum is a great resource to find out about particular pressings. My go-to site for vinyl related questions.

That said, there are some details that can help you make educated decisions.

1) where the LP was pressed (currently IME: Good=QRP, RTI or Pallas;Bad/Inconsistent=United, Rainbo; Rainbo for example pressed the Beatles reissues which there are tons of QC complaints about).

2) Who remastered the record (Safe bets: Hoffman, Gray, Bellman)

3) Limitations of the original pressings (poor vinyl quality, rolled off in the bass, poor pressing plant)

There have been some fabulous reissues lately, that were clearly superior to my early pressings: QRP's Tea For the Tillerman, MoFi's Music From the Big Pink and the Basement Tapes jump to mind.

GMC- we are on the same page. I like your wall of vinyl at home.
Viridian- excellent point. I did touch on it in my earlier post here, but didn't
spell it out as you did. Which may be one reason why mastering engineers
have to make dramatic changes in the sonics? Or is it also catering to a
brighter, 'clearer' sound that people may prefer after getting used to digital?
Part of the death of good sound is complex multitracking, where having all
the musicians in the same room and a sort of bleed through of the acoustic
is lost. That may be why some of the 'audiophile' recordings like D2D sound
good, apart from skipping the tape altogether. (unfortunately, most of the
natively 'audiophile' records leave me cold, musically).
AudioTomb- are you talking about those new Apple reissues on vinyl?

This subject is one of those that rather turn me off from vinyl to a certain extent. Yes, I heard some original pressing that is noticeably better than more recent reissue or current audiophile reissue. However, if the music is good enough , the difference between pressing is not significant enough to deter me from enjoying the music unless the LP is defective or have way too much surface noise. If I find an album that I like enough on reissue, eventually I might try to locate original album if I think the music is good enough for the premium price asking on some original pressings. My rule of thumb, if it is an album that I really like and I only have one copy, it will eventually fall off my hand one day and get scratched badly. If I have more than one copy, none of the copies will ever get damaged! :)
Stockfisch is the other label that I really like their new LPs as far as sound quality is concerned.
For country of pressing, if the band is a UK band and is first released in the UK before the US, then I'll try to get UK and vice versa. Generally I don't like Japanese pressing very much as they almost always remastered the album first and the typical EQ for Japanese record is usually not to my liking when comparing to the original western counterpart. But that's just me though and I have to confess that my sample size of Japanese pressing is limited but that's what I found so far.

I agree with Viridian about 40 to 50 year old tape loss,music I listen to.I stopped buying reissues years ago.There are so few exceptions it's not worth wasting the money to find out for me anymore.I got tired of wasting 25-30 bucks for an LP and after 2 minutes of play it comes off the TT never to be played again,original better.The tape loss on Zappa's Hot Rats classic reissue is unbearable for me to listen to.Reissued vinyl of 45 year old recordings is just not happening for me or worth the gamble to buy.