I haven't ever tried one of the F1 springs, but would guess that they are very, very good. I've never had an issue with any of my Venom or V-Mach springs......The oldest V-Mach spring I have is the one that came in the kit that I fitted to one of my 77s in 2010 and is still performing impeccably, as are the Venom ones in my Venom tuned 80s and these will have last been serviced by Venom at Cradley Heath back in the late 80s / very early 90s.