The advantage of the twin resin tank softener is that it regenerates exactly when one tank is depleted and switches service over to the other tank which is more efficent water and salt (potassium, if you choose) use.
Also, The Kinetico regenerates the resin AND makes the brine with softened water which makes the resin last longer. In high hardness and iron water conditions I don't like the idea of regenerating the resin with the untreated water, kinda like washing clothes with dirty water if that makes sense, but that's just my opinion.
Since your neighbors have Kineticos, and are on the same water as you, ask them lots of questions. Ask about the Kinetico dealer, good service after the sale?
As far as local indpeendent water treatment pros, look to the Yellow Pages, usually under "water treatment".
Upflow or countercurrent regeneration, regenerates the resin in the opposite direction of the water service providing a more thorough regeneration, more complete rinse, and longer resin life. You can Google "upflow regeneration" or countercurrent regeneration" to satisfy your engineering curiosity with way more info than you'll ever care to read.
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