Jason covered the basics. Just search the forum on the topic of UV/Ozone/Alternative Sanitizers and you'll find lots of discussions.
As for having an SWG or not, that should be up to you. However, as we recently learned from a TFP user who works for a Texas based pool builder, the sub-contractors used by the PB are driving the wedge between SWG's and pool owners because they are frustrated with warranty claims on their work. A high quality stone mason will know how to do his tradecraft when salt is involved. There might be extra costs with sealing stone or a reduced selection of materials that can only be used with salt, but a good mason should know how to navigate it. The problem is, PBs want to use the subs that they have and if the sub refuses to warranty their work on a salt pool, then the PB is left holding the bag. Many PBs refuse to to take on added warranty risk and so they simply pull away from offering salt as an option. The science clearly shows that salt can be detrimental to certain types of stone and masonry work BUT there is no way to know before hand if it will occur and one has to use caution in selecting the right materials for the job. So, if you really want an SWG pool, you should get one but you will have to negotiate with your PB and there may be greater restrictions on what they will warranty.
UV and ozone will not keep you from needing chlorine. In fact, all the manufacturers of those systems are required by federal law to state that you must maintain a proper chlorine residual in your pool as UV and ozone are not primary sanitizers. So, as Jason said, if you have to maintain chlorine anyway, why waste the time and money on those alternatives? They claim that their systems allow you to use "low chlorine" but that is mostly bogus as residential pools are not designed with very sophisticated hydraulic systems and therefore have a hard time maintaining low chlorine levels without dead spots occurring.
Oh, and by the way, all pools that use chlorine (and acid to balance pH) are salt pools. All pools build up chloride over time as that is natural end result of all chlorine oxidation and disinfection reactions (chlorine is reduced to chloride and some else gets oxidized in the process). So it is not uncommon to find pools with high levels of chloride in them after just a few years especially in areas where fresh water exchange is infrequent.
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