Originally Posted by Pocono
I cast a 9'0" 5 wt. One when they first came out in the Summer of 2010. I cast it side-by-side with my Sage Z-Axis and, in the end, I kept the Z-Axis and let the One go. I think I posted a short review on the One back at that time.
Last Winter for a project, I built a Sage One 6 wt.; for heavier streamer fishing and when the wind picks up. It's a very nice blank.
George Anderson compared the ONE with Hardy's Zenith, and wasn't excited about the Sage until they got to the 6-weight: Sage One Fly Rod Review - Yellowstone Angler
I've thought for a long time that not all rod designs would work well in all weights. That's based on actually fishing some of Sage's rods in various weights, and wondering, "Why did they ever make this rod in that weight?"
That's not to say the ONE in a 5wt isn't going to be a fantastic rod. I have zero experience with them.