I'd bet that Jet-dry is similar to photo-flo, but Jet-dry has colorants and probably other junk in it I wouldn't touch with my negatives.
Use Photo-Flo if you have issues with spotting. If you don't have issues, then just use plain tap water or distilled water. I personally don't have problems with spotting, so I don't use Photo-flo. Freestyle sells their brand of Photo-flo, and there are several other producers that make a similar product that is cheaper than Kodak's, but in reality you use the stuff in such high dilutions and it lasts so long that I would just buy Kodak to avoid any possible QC issues.