There's a lot to be said about this, although its hard to beat a good quality relay. But not having to run discrete wires for every single switch and dealing with all the associated complexity makes a sPOD or similar device attractive - esp. for a retrofit. Unfortunately, the expense seems to be horrid as well for most of the solutions.
We went from using MOSFETs to a relay system in an autonomous, remote deployed system. There wasn't anything wrong with the previous MOSFET setup, but we felt we were better off long term with mercury wetted relays. That was 22 years ago, its still running - this is NOT something you want to break as it costs thousands in ship time to go fix/replace the thing. No smartphones though!
