I have Spoons, Fluxes and Primes and I like them all.
The Flux does have a softer feel or more padding, not sure which but it is a comfy saddle.
The Spoon is the the same shape and design really, I have ridden a HONC, two Mayhems and the recent 60k MADORC all on my Roberts complete with its Spoon (saddle that is, not the cutlery) and comfort has not been an issue, although it is noticeably firmer. At least it feels that way to my delicate derrière.
The Prime is my current fave road saddle. I did a weeks riding in Scotland in June on my Rourke and Prime (shame it doesn’t have a Spoon) and had no saddle issues whatsoever. I also did a 100k sportive later in the summer, as well as all the usual day to day riding and I’m just about to put a Prime on my KTM training bike.