The 5020's were good stuff. Reliable and fairly simple to work on from the little I was around them. The dumb thing about all this EPA stuff is how much environmental impact does it have on manufacturing a new engine/tractor/car/whatever from scratch vs maintaining a decently efficient old thing? My old Freightliner gets just under 8mpg, essentially the same truck but a year old is getting 5. So burning 3mpg more fuel is cleaner? The math just doesn't add up.
Welding is definitely faster and in many cases works just fine. I like stitching those pieces back in when I can just because once it's done you can't tell there was even a repair done unless there was text that was obliterated in the process.