Any Experience of Water Softeners (Recommendations or Otherwise)

Hi All,
we’re in the north of Lot et Garonne and suffer with very hard water. We intend to fit a water softener. We’ve been advised that we require a fairly large unit to cope with the number of simultaneous showers that we have running at times and have been proposed a Cillit model.

Does anyone have any experience, suggestions, positive or negative recommendations for any water softeners?

Thanks in advance.