Feature comparisons between these two obscure the decision rather than clarifying it, because the products are not variants of the same thing. The clearest way through is to list the complaints hard water causes and mark which of them each approach fixes, since that is what a household is actually buying.
Scale in the heater and appliances
Both help, which is why both are sold. The salt based softener removes calcium and magnesium outright, so no new scale forms anywhere and existing deposits lift gradually over months. The saltless conditioner converts hardness into microscopic crystals that resist bonding to hot surfaces, greatly reducing deposition without removing anything. On this complaint the difference between them is smaller than the marketing on either side suggests, and both are a substantial improvement on nothing.
Soap, lather, laundry and skin
Only the salt based unit changes any of these. Poor lather, soap scum in the bath and on tiles, stiff towels, detergent working badly and skin feeling tight after washing are all caused by the minerals being present and reacting with soap. A conditioner leaves them present, so all of it continues exactly as before. Households that buy a conditioner expecting the shower to feel different are the ones who report disappointment, and the expectation was the problem rather than the product.
Spotting on glass, screens and taps
Only the salt based unit again. Spots are dissolved minerals drying on a surface, and they dry the same whether or not the mineral has been through a conditioner. A hardness test after a saltless unit reads exactly what it read before, which is the expected result rather than a fault, and it is worth knowing that in advance. The USGS classes water above 180 mg/L as calcium carbonate as very hard, and the visible spotting tracks that figure closely.
What each costs you to live with
The salt unit needs a drain connection, salt carried and loaded, space for two tanks, water sent to drain at each regeneration, and it adds sodium. The conditioner needs none of those, which is why it suits apartments, septic systems, properties under discharge restrictions and anyone avoiding sodium, but it does need a sediment prefilter and carbon on chlorinated supplies to protect its media, replaced every few years. Our saltless softener guide covers the specifics.
Questions people ask about salt vs saltless water softener
Do both stop scale in the water heater?
Both help substantially. The salt unit removes the minerals; the conditioner stops them bonding to hot surfaces.
Which one improves lather and soap scum?
Only the salt based softener. Those complaints come from the minerals being present, which a conditioner does not change.
Will a conditioner stop spotting on shower glass?
No. Spots are dissolved minerals drying on the surface, and they still dry the same after passing through a conditioner.
Why choose saltless at all?
No drain, no salt, nothing discharged to a septic system and no sodium added, with good protection against appliance scale.