I'm brand new to On and bought the cloudflows for a racing shoe. The exposure to cloudflows might have converted me to exclusively run in Ons. This is an amazing all around shoe that I have found myself running my fastest times (from 5K to marathons), as the show feels much lighter and provides a really strong energy return. I can feel this as I can run about 20 seconds faster per km without feeling like I'm pushing myself harder. The cloudlfow also stays super comfortable on long runs (after 25 or 30km you don't feel it in the knees or feet as much as other shoes. It's hands down the best shoe I've run in. Next for me is buying the Cloudsurfer as a trainer and Cloudventure (for trail running). I'm super confident that On has the best running shoe technology.
The only con I have about this shoe is the durability. Since it's so light, I wouldn't imagine this would be a durable shoe after 400-500km. However, I will gladly buy another pair at that point since the overall performance is well worth (the anticipated) shorter life of the shoe.