The wife would never let me hear the end of it if I didn’t install a water softener. 🙂 Camco and On The Go make RV specific water softeners, but I imagine any portable water softener will work just fine. I installed an “On The Go” portable unit.
Is it worth it? 100%. For the same reasons you’d want one in your house – to protect your plumbing and appliances, reduces maintenance and cleaning of sinks, showers, and appliances, prevents hard water spots, etc.