Choosing between Reissue and Original pressings

Original copies today can be a 'pot luck'. Even if the vinyl LOOKS good to the eye under good light it may not playback well. Groove damage by an improperly set up cartridge or a worn stylus is not able to be seen under even good light by the naked eye. Damage due to static discharges from all too many previous plays (a severe enough static pop will likely create micro craters in the vinyl groove) also cannot be seen. That said a good condition original esp. pre say 1985 will probably sound good.

New vinyl today as remastered copies can sound fabulous but too can be hit or miss depending on the quality of remastering and the quality of the new pressings. But all in all they should be payable and enjoyable. You do get guaranteed nice clean covers and inside liner sleeves as a bonus.

It's all pros and cons be it sourcing out older vinyl or buying new pressings.

I have many first release and japanese pressings from the late seventies only played once straight to nak cassette back in the day

Most remasters don't hold a handle

In jazz blue note, riverside, prestige and impulse have been great

Classic records is hit or miss
I've bought quadrophenia twice and both were horrific - totally congested mess

The latest beatles remasters are as if you put a wet blanket over the proceedings. People swear by them, but probably haven't heard a uk original, german import, or the 1978 bluebox

It's hit or miss and worse no-fill and odd residues, fingerprints, in the old days it was just crackles from impure vinyl

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.