The kinetic energy of the mass of exhaust gas carries it along the exhaust pipe, and causes a pressure build up ahead of the mass of gas and a partial vacuum behind it. This principle is used in a tuned exhaust system.
Culligan - $2352 ($2053 w/o R/O unit) Culligan Gold Series (10), Good Water Machine. If I were to look at price only, I would go with either the cheaper Ecowater system w/R/O at $2698 or the Culligan system. At almost $4k, the Kinetico system seems greatly over priced.
It would certainly be a lot easier to decide between Culligan and a competing water company if you had a list of prices for all of the various units at your disposal. The general consensus of most people is that some Culligan water softener prices are somewhere in the neighborhood of outrageous. Some people have claimed to pay anywhere from $350-$700 for a Culligan water softener, and that is for the lowest priced models, which are not likely to be the ones recommended by the Culligan salesperson who visits your home.