They're very close, to all intents and purposes. You get the claimed 904L steel with the ARF version. But the experts around here have favoured the JF out of the two. See this comparison post, and then the comments following it:Is an old JF better than the current ARF?
https://forum.replica-watch.info/fo...-16610-lv-submariner-904l-kermit-photo-review