"But this makes me curious why all the manufacturers use in-line cells instead of the wall mounted like the old "Pure&Clear". I've heard that inline chlorine generators also degrade the pipes . Wall mounted cells is also much easier to clean, and to replace. Only down side is it is subject to damage from kids, etc."
In-line cells are the standard. Wall Mounted cells directly in the pool, are called convection cells. Basically running independent of the pump circulation. This is a much more efficient design, but no way to safely install the cell and still maintain an efficient system. AutoPilot had an Indeck convection system with a small power supply that was capable of controlling up to 30,000 gallons for less than $500. But the amount of maintainance needed to ensure proper circulation caused some premature cell failures. IF the indeck canister in which the cell was located in, was maintain weekly, this system would have been perfect. Very similar to the Kreepy Klear, but no cell in the pool to worry about.

Regarding in line systems dedgrading the pipes.... poppycock! Well, unless it is old copper pipes. PVC pipes do have any problems with salt systems, or else 90% of Australian Pools and up to 40 - 60% of pool built last year would be in some sort of disaray.
There is nothing associated with a salt system that would cause any plumbing problems. High chlorine levels will do more damage to the equipment than high salt levels.