Personally I think they are great. Mine is semi-broken, so have to regenerate it manually, this means it runs out of soft and starts to bleed hard water every few days. Washing in hard is horrid when your used to soft.
Cost after purchase/fitting works out to be about £1/pp/pm. Easy save that on using less soap, washing powder etc.
Mine is a Kinetico (sp?) 2020c, which cost a fortune. Don’t think Id get the same one again, had nothing but trouble with it. Having said that a couple of friends also have them, and are happy so far. I may have just got a dud.
If I were to buy again, when I finally get round to replacing mine, I would get one with an electric timer and proportional brining. Job done.