Unfortunately there’s very little notion of nationwide quality for Amtrak. I’ve taken it between NYC and DC plenty of times and it’s always been great but I wouldn’t automatically extend that experience to any other line in the system.
I believe Amtrak owns their tracks on the Northeast Corridor which they don't in most of (all?) the rest of the country where they conflict with freight. Amtrak basically makes all of their money on the Northeast Corridor and loses it on most of their other routes.
