Do you actually know someone that had the plastic line on a mechanical oil pressure gauge fail? If you do then you also know a lousy installer. Keep the line clear of exhaust manifolds and or jagged sharp edges and you will be fine. If you are worried about the possibility of a plastic line failing from a fatigue crack, just remember to change it out every 50 years, or install a steel or copper line. The metal lines are also available at Summit. With metal lines put a loop in the line close to the engine to absorb vibrations.
The problem with electric oil pressure gauges, they are dampened, so there is no immediate feedback. I have not looked for one of those but the electric gauges typically are only scaled with a L for low and an H for high,, mechanical gauges report in numerical psi.
