+ Nature2 is mostly useless -- search here for threads about it http://www.poolsolutions.com/search.html

+ Non-salt is cheaper than using an SWCG (salt water chlorine generator) IF you stay on top of it, but it's less convenient.

+ Salt requires you pick salt compatible components. Most AG pool warranties are voided by salt, and most older heaters are not compatible. (Plastic solar systems are fine.)