I have one and I love it. Our water is so hard here and now I have no more water deposits anywhere. Everything is cleaner. Our water doesn't feel "slippery" like salt softeners. No maintenance really, just dump in the potassium crystals.
Here's the website of the manufacturer
www.sigmawater.com
It was like, $2000. Kinda pricey, really, but I love the results. I'm sure I could've found I cheaper one, but I'm happy with the company I purchased from.
It even makes our tap water taste better!