SPRey I can agree that the smart plug may make a more secure connection vs. the Marinco.
However the Marinco work fine as long as yoe make the extra effort to ensure the locking ring is snug and secure. Honestly many don't which allows for a lose connection. A 90º connector at the RV also reduce the stress at the twist lock connection.
What really kept me from going the Smart plug route is the smart plug is a unique proprietary cord that does not fit many of the adapters/pigtails I already have.
I do not want to abandon all the adapters I have already invested in. I do not want to be without adapters because you never know what you may run into when it comes time to plug in.