USB - each provide an excellent method of sanitation when following TFP protocol and maintaining the [fc/cya][fc/cya] ratio.
With that said, having done both, folks would have to pry my swg from my dead cold hands
To me, the convenience trumps anything else. The stability of the swg in terms of adding precisely what you need, instead of dosing higher to account for burn off, also appeals to me. And the water is awesome
So, for me the choice is clear, but sometimes mfgs promote SWGs as an easy button, and I do think that's a bit disingenuous. Its not exactly "set it and forget it." Successful swg transition still requires good testing, observance, and dialing in or tweaking production. You may have to control oh more until your TA is at the happy place. Folks who retrofit to swg should also review their equipment for corrosion potential (eg are those bolts really 316 stainless...should that light ring be swapped out) and ensure that the swg, and everything else in the pool, is correctly bonded. Galvanic corrosion is a possibility given the method of production. And while all pools have salt build-up, obviously there's more with swg, but about a tenth of seawater...so not in itself a dramatic amount of salinity.
Lastly, swg is best at producing a small, steady level of FC. If one needs to slam or the water is cold end-of-season, you still need a bit of liquid chlorine in those instances to boost as most cells don't produce in cold water.
Another tip is to buy a cell rated double or more if possible for your pool size. In that case many folks can "beat" liquid chlorine cost handily because their cell lasts longer...some members report 7 and 10 years, for example, on a cell warrantied for 3 years. I'm using an aquarite T15 rated for 40,000 gallons on my 24,000 gal pool.
As such, it is capable of producing in my pool 7.9 ppm FC if run at 100% for 24 hours. If you're shopping for cells in the future, look for the daily production rating, then use the bottom part of pool math to calculate chlorine gas for your gallonage. That will help you get production dialed in