Ok, first off an SWG pool is a chlorine pool, it just generates the chlorine by passing an electric current through salt water (salt is Sodium Chloride, he current separates the Sodium ion from the Chlorine ion). This allows for a somewhat easier chlorination system, but there are a couple of down sides, the salt water can be corrosive to some soft stones, like flag stone that is very popular in Texas. Also the SWG generating cells have a limited life and must be replaced every few years, if they last their typical expected life the cost of operation of an SWG vs manual chlorination is about the same, but if they die prematurely the SWG can end up costing you more money to operate.
As to Ozone, the short answer is just say no, the long answer is a well built Ozone system can in conjunction with other cleaning practices provide a reasonably sanitary pool, these are often used in Europe where they seem to have a cultural hatred of all things Chlorine. But this is not the typical small residential ozone system found in the U.S., instead we are talking systems with multi thousand gallon holding tanks, large ozone generators, etc. By contrast the inline ozonators sold in the U.S. are at best supplemental oxidation systems, which are only needed in certain special circumstance chlorine pools, primarily indoor pools, and perhaps smaller warmer than average high use pools such as those used for physical therapy. Ozone generators can also be handy for supplemental oxidation in hot tubs, another elevated temperature, relatively small high bather load (to area) application.
Having said all that the choice of type of chlorination system SWG or manual (or metering pump), should be fairly far down on the choices for building a pool, far higher should be type of pool (size, shape, depth), material selection, and equipment / automation choices, and of course placement if you have options in your yard.