they probably provide more throughput.

Meaning more gallons per minute will flow through them to your tubs, showers, ect... than with the lowes model.

Some of the higher end units have two resin tanks. When one is being regenerated, the other tank is used. Whereas with a one tank system, while the system is regenerating, any water used in the house is unsoftened.

Some cheaper systems regenerate on a fixed schedule, every X days, many of the more expensive one measures the amount of water passing through them to determine when the resin needs to be regenerated.

Some one explained to me once about how a larger unit can need to be regenerated less frequently, than one just barely big enough to accomplish the job, which can save money over time on salt, although I don't think I understood HOW this is supposed to work.

I learned all this only after buying and installing an off-the-shelf water softener from Lowes about 8 years ago and decided that when it fails, I'd replace it with a better unit. However it doesn't seem to have failed yet.

You may have more luck getting more and/or better answers in the plumbing forum.

This post was edited by bob_cville on Mon, Aug 25, 14 at 15:57