In my research, I couldn't get any definitive information on the cost savings of going with SWG. In fact, if you factor in the up-front cost of putting in the SWG cell, etc (roughly $1000), you could make the argument that recouping your up-front cost will take many years.

I wanted SWG not because of any potential cost savings, but because of the low maintenance aspect of it. I won't have to store chlorine, nor have to put chlorine in manually. If I ever have to leave town for a week or two, no worries about coming back to a green pool. Not to mention the "softer" feel of the water in a salt pool.

Regarding the corrosive properties of salt affecting the structure, plaster, etc - I couldn't find any definitive evidence of that either. The PB we selected had an unconditional warranty on their pool structure. Given that they did salt pools exclusively, I took this to mean they had no concerns about salt corrosion.

Having said that, we did go with a pebble finish which negates the issue of salt on plaster, if there's any truth to that.