I have casted the radian only once and it was on a casting pond, I didn't fish it so I don't think I can give you an accurate rating of the rod. However, I have fished both the one and z-axis rods in 590 configuration. If I had to rate them I would say my favorite is the z-axis by far, then the radian, then the one.
The z-axis with it's soft tip is far superior to me for short line nymphing techniques, you can feel all the lil bumps along the bottom and can feel any take so easily all the while highsticking. The dry fly presentation is also bar none due to the bendy tip. I believe the combination of the fast action and soft tip is hard to beat as a fishing tool.
The radian, had a lot of line feel and appreciated the craftsmanship soooo much, that rod is gorgeous!
The one rod just doesn't do it for me, I felt that with nymphs and streamers it just doesn't respond well. The cast with weighted flies feels choppy to me and while drifting sinking stuff the one feels dead, its not a good wet fly rod at all IMO. As a dry-fly rod the one is incredible however. Distance casting small dries is a dream with it.
To be honest out of all these rods I prefer the sage vxp. I have stated this before, but its more of a progressive medium fast rod. It maintains a stiffer tip however, it handles both dry fly and nymph and streamer perfectly. That probably doesn't help you, figured I should throw that out there though, it doesn't have the $800 price tag as the others, but it certainly is just as good or better than all stated IMO may be worth a try.
Anyway, if I were in your position I would without a doubt keep the z-axis, or go try a vxp as well. Those faster rods are fun to cast in the parking lot or lawn, but casting and fishing are two different things, you may want to consider that.
These are my opinions, sorry if I offended anybody
No offence at all, different opinions are why we have forums. The thing I'm picking up here is how individual we all are. I did put that One on layaway and still own the Z-Axis so maybe ill hold on to it and compare next spring, but having fished it three times, I haven't warmed to it yet. On this thread we have multiple very experienced fisherman who mostly love the Z and differ in their opinion of the One.
I fish dry flies or dry with a dropper 80% of the time, but based on your observation, maybe I keep the Z for nymphing and the One for dries. It just seems to me that casting dries is way more critical than weighted nymphs, I actually use my Scott G-906 for that and it does well. I also just bought an Echo-3 10' six weight that may work well there.
I'm hearing good things about the Radian in 5 weight, but I'm looking for a 9'6" 7 weight for shad, bass ponds, and larger streamers in general. I've cast the One and have a high opinion of it. I also have a soft spot for Scott's, but I'm wondering how the Radian compares to the One in the heavier models. Any experience here?
The Z-axis is my favorite rod, and I love casting it. But I read so much good stuff about the Radian that I sold my wife's rod, gave her my Z and ordered a Radian. I'm still getting used to it, but I like it better and better. However, I still could switch back. I tried the One 590 and didn't care for it. Too stiff. But I got a deal on a One 696 on which I cast a variety of lines including a 7 wt. Works great as a smallmouth rod.
I tested the Radian against the "One" side by side. Everyone at FRA loved the "One" & thought it would also be my pick. I will be honest though and must say that one of the sales reps there did tell me he used to work for Sage & he is a bit biased. I kept that in mind. So I casted the two rods and found that the "One" just wouldn't perform for me. I couldn't feel anything, and the line flew out in front & then just fell to the ground. Then for the Radian, it was like a choir of angels were singing as the line flew over my shoulder and laid very nicely down in a straight line. The sales person said watching my stroke he couldn't figure it out, my casting stroke was the same for both rods. So I tried the "One" again and nothing happened. I couldn't get the line to lay down. I couldn't feel anything. As I played with the radian I could feel the power from the butt section trasnsfer through the mid section to the tip. Not with the "One" With the "One" I wish I had a pinata to hit. And one more thing about the Radian is that when I hook into a fish, this is the ONLY rod that speaks to me saying "relax, I got this." I LOVE this rod! If this rod came out 30 years ago I never would've gotten married. I can take it anywhere, it's cheaper than my wife, and it asks nothing in return. The perfect relationship. OOOh,Valentines Day is near.
As the OP a year and a half later I ended up selling my Z-Axis to a forum member, buying the 590 One during the winter, then based on earlier casting the Radian at my local shop, trading the One for the Radian. It took a couple lines before I settled on a Rio Gold and fell in love with the Rod. I fished it a lot last season and liked it more and more as I adapted to its faster than my G-series feel.
Looking back I kind of think my troubles with the Z-Axis were line related as at first my Radian felt very much like the Z Axis. If I had experimented more with it I might have kept it and been happy. Regarding the One, the one time I tried it against my Z Axis, I much preferred the One and felt the One and Radian were close "fast with feel" type rods while the Z Axis was the odd rod out. That totally goes against every review and comment by those that know a lot moire than me. Again, I think my troubles were all line related.
Lastly, I have to admit that despite my liking the One when I test cast it, S & S made me a little nervous about keeping it as my all around Montana rod. He said as wonderfully as the rod was, it was also was pretty unforgiving and required constant focus or things could go bad fast. Like I said, I found it easy to cast in a short parking lot session, but wondered if things would be different all day on the River. I knew the Radian had the opposite reputation and coming from decades of fishing a Scott G, I liked the idea of a Scott sweet rod modernized so I switched.