I would then recommend the softener. If you don't put the salt in it, it just doesn't soften the water. The RO filters and membrane reduce water flow when used, and eventually will stop all water flow. Like you said, there are many different types of systems with varying costs. I would use your water bill to estimate your monthly usage in gallons and select a unit rated for your usage plus about 20% above your annual average monthly usage!(hope that came out right. Take monthly gallon usage and average it over a year, then add 20% that should narrow your results down to only a few systems. Then look at features and maintenance requirements from there. Either way, it's gonna be expensive!
The difference between stupidity and ignorance. Ignorance is doing something wrong and not knowing better. Stupidity is knowing better, but doing it anyway. Don't be stupid!