Since 2013 I've been using F-HOT Slalom fins. I was one of the early adopters and still happy with these top fins!
In that year I compared them to several other Salom fins after I have been using the Choco Fireblades for several years. I wrote my review on fins some time ago.
What I really like is the light and free feeling these fins give my boards. You can put pressure on them early and after that they give an even and constant lift when accelerating, with good control. That gives confidence, never strange or unexpected moves from the fins. You can focus on other things. :-)
Ross Williams uses the F-HOT RS series that have been developed after the S series. More focussed on PWA conditions, downwind course, fully powered at the limit. What I hear is that the RS is more technical to sail but faster when you can handle them.
With my weight (78kg/184cm) I use my set most often in well powered conditions, not on the high-end. The performance that the fins give me is more dependant on me than the fins. I feel that I did not get the max out of the fins yet and I expect more is possible. Also the support on the fins that Steve Cook gives is also remarkable, a real craftsman. I crashed one of my fins and Steve repaired this fin as new!
Please let me know if you have questions or need advice on what fin type/size for your set. Happy to help you.
See you next time, Mark