My 95 Trek ZX7000 came to me with a Vetta TT Tri-shock. I replaced the vinyl cover with leather and found it very comfortable (5'11", 155 #). After I got my Cannondale CAAD3 R600 I got another Tri-shock (for free due to some damage) and recovered that. Very comfortable for me. I now have 4 of them and just found a 5th. They seem to be discards and end up in bone piles. I find them easy to recover in leather and they look great. They just suit me.
My '80 Nishiki International came with a Vetta Anatomic (yellow!!) and it's also very comfortable so will stay on that bike. Did 53 miles on that yesterday with no complaints. I now have a very nice late '60s Wrights W3N which has been on the trainer mounted Moto all winter. Its comfortable but not more so than the Vetta's so I've not moved it. I should put it on the open road but the Tri-shocks are just right and lighter so I drag my feet.
I have found that even the Tri-shocks varied a bit in stiffness and long haul comfort. But for the price ($0 to $5) I can experiment and use the best ones the most.