Bernstein's Paris set is very good unless one insists on a lean HIP or proto-HIP style. It has some faults (like being string dominated) but it's very dramatic and expressive. The 83 g minor and the slow movement of the 86 are among my favorites, the 85 is probably not lithe and elegant enough but overall it seems obvious that Lenny cared about the music. They are individual and energetic, if for today's ears sometimes unconventional readings. (I do not know his London set well enough to comment.)
It's been a while but I have over the years listened to about 10 complete and partial recordings of the Paris symphonies and if I could keep three, they would probably be Bernstein's (the only "big band"), Harnoncourt's (the most colorful and original but sometimes also irritating) and Marriner's. Marriner is very elegant, fleet and supreme in the "lighter" ones (84, 85, 87).
But admittedly I have not heard other "big band" contenders, namely Ansermet, Dutoit and Karajan (I think they are the only "important" sets of this music I have not heard). In my experience, Bernstein is most frequently recommended among those. I have heard Dorati and Fischer and Bernstein is clearly superior. The others were all HIP or chamber, in addition to the one's mentioned: Brüggen, Kuijken, Weil, Wolff, Fey and Goodman (82-84).