I use mechanical as I like having a "live" gauge. I'm seen electrical ones act up and oil pressure is pretty important when it comes to an engine. Every mech gauge I've bought has come with the plastic tubing which is not allowed for a race car. I've had the copper line crack on me twice in my time. Both times where the line would be in the fitting at the engine. After the 2nd time I changed over to a -3an braided line, not more cracked lines for me. Not all gauges are compatible with braided lines. I had cheaper gauges for years, but ended up purchasing an Autometer oil pressure gauge when I did the braided line setup.