For PS I would advise to study and observe for a long long time, before buying. Be a stalker on PSF and dealer sites. Distinguish what is really rare and outstanding, even among the PS world, apart from the “run of the mill”. Otherwise you run the risk of straddling the borders between PS and core.
Then, pounce without hesitation when a special top, a special neck, or a special complete dealer spec guitar becomes available. You have to be fast when the time comes.
PS is great, no indeed it is irreplaceable and unrivalled, for that really rare, out of this world specimen that pops out once a while. There is no rare Gibson Custom Shop guitars produced anymore, cos every guitar they churn out is essentially the same, same woods, same look etc.
I once asked a dealer, does PRS have African Blackwood necks if I wanted to do a PS. Not knowing at that time what a monumentally big ask that was. They replied well it so happens they have ONE such neck blank in the vault. I later found out you just don’t find African Blackwood neck blanks anywhere, not just the PRS vault.
Rest is history, never looked back except with fondness. I would say my entire guitar collection, including the disappointments and misses, has been worth it just for that one single hit.
One final thought if you will. If something is rare because nature makes very little of it, it is truly rare. By contrast, limited editions really mean unlimited.