I think Crosman vintage CO2’s hold up the best and are the easiest to reseal. I think they clearly focused here during the golden era and their engineering is hard to beat.I think Sheridan and Benjamin pumpers are the best built. That said they are not the easiest to reseal that would go to Crosman. With Crosman pumpers I think you need to pick your spots. They were not as consistent.
In CO2, the Crosman 160 and 180 series are outstanding. Well designed and made, rugged, accurate, shoot for many years and easy to work on.
My '67 Sheridan has had only the pump cup replaced. I shoot it regularly. In CO2, the Crosman 160 and 180 series are outstanding. Well designed and made, rugged, accurate, shoot for many years and easy to work on. The earlier bulk fill guns are excellent as well.
I can only echo what's already been said. In my somewhat limited experience, Sheridan C model and Benji 342 are very fine rock solid pumpers. I recently picked up a Crosman 101 that needs resealed but HEAR I will be impressed with that, so the jury is still out.With my love for Co2 I can honestly say a 3rd variant Crosman 160 is the pinnacle. The ease of resealing if needed, the excellent trigger group makes me wonder why Crosman ever stopped using it. Heck the QB-78 is a direct (metric) copy of it and STILL been produced and has it's own loyal following. AND NOW... I am eagerly awaiting delivery of my 114 bulk-fill Crosman... that is a whole other page I am about to turn in the book of historic vintage airguns.
The Benjamin 312, Sheridan C models Silver or Blue Streak and Crosman 101 any period are all great reliable pumpers and very easy to service, repair and maintain as they were all designed with these factors in mind. They just don't make them like that anymore.I hope to add a Benjamin 342 and 317 one day and a few more Crosmans such as the 140 and 1400.Another I am impressed with is the Smith & Wesson Model 77A, much like the Crosman 140 in design but harder to find.I have one Co2 - Crosman Trapmaster 1100 that needs work as it leaks so I can't say much on Co2 reliability until I get this on working correctly.
These are all great air rifles. But what makes them great? Is your favorite a vintage survivor covered with dings and dents demonstrating that it has seen prolonged hard use? Is it an NIB attic find? I own three Crosman 1400’s (2 shooters and a basket case). Two have seen hard use and have slop in the pump linkage. The one I got from 19Sheridan57 has a tight linkage indicating that the gun had not seen much use or abuse. The OP’s question was which ones hold up the best? Age is a factor but use and abuse should be considered too. I’ll bet my grungiest, rustiest, old Crosman is as tough as any pampered Benjamin or Sheridan.