To me, for what it is worth, either type works fine for our purposes.
My only concern is a "mechanical"
oil gauge. I simply do not like the idea of a plastic line, or even a soft copper line running from the engine, down the side, crossing the gap to the firewall, through the firewall and then up to to gauge. If this lines breaks between the engine and the firewall you have a horrendous chance of fire.
If it breaks from the firewall to the gauge, filling up the cockpit with hot
oil would not be a fun thing either. Then, if it does break or leak on the outside it takes literally seconds to pump all the
oil out of the engine. Am I paranoid about this? You betcha! It happened to me, put a rod right through the side of a brand new block.
Running either a nylon or copper line is asking for trouble. Kind of like a computer: The question is not, will it crash, but when!
Back to my corner.
DV -- The numbers are screaming -- are you registered?