With VS or KL you can use the DeltaOne lounge in JFK which IMO is superior to the Clubhouse. You could of course also probably fly DL metal on the US-LHR leg if the timings worked.

With AF you could potentially upgrade a leg to La Premiere ($2k ballpark) which is a nice treat (especially since you’d be able to use the lounge on the connection).

Bottom line I think there are pros and cons to all the options and no clear winner.