I bought a pair locally and have done a 100k, 3k meters with 20% gravel ride on them (Fishrock) with Armadillos and a bunch of additional straight road riding (with a lot of climbing) with GP4000sII tires. I've been running them at 80 psi front, 85 psi rear. I FTP at 290 and weigh 157 pounds. Most of my riding is on 303 firecrest tubulars laced to WI TI11, followed by Bora Ultra 35 tubulars and then HED Belgiums laced to CK R45. I've exclusively ridden them with a Baum Corretto.
So with that background:
1. They *feel* fast. Probably placebo. But I have been putting up good times on them. Eg today's ride: https://www.strava.com/athletes/12436
2. The GP4000sII 25 clincher, using digital calipers, comes out a hair under 28mm. I've run "wide" wheels for a long while, but none that produce such a wide tire. The HEDs are 17mm internal and I run 25mm tubulars on the other wheels, which keep their size. I really like the extra width. Gives more confidence in the turns on the fast descents. See the PR on the very steep backside of Hawk Hill today. And I wasn't trying and didn't feel like I was pushing.
3. Beyond the width, they're just confidence inspiring on descents from a handling perspective. I assume this is a combo of stiffness and weight. Their braking, however, isn't so great, which I'll get into below.
4. I get no brake rub with about 2-3mm of space. I get brake rub on the 303s laced to the WI TI11s all the time. I have to run the brakes wider. With Zipp hubs, even worse.
5. I had a fair bit of crosswind on the Golden Gate Bridge today. No problem. Not necessarily better than a Bora 35 or Zipp 303, but definitely no worse.
6. They're as comfortable as the Bora 35s. I find the Bora 35s to be very comfortable. I find the Zipp 303s, same tires, same pressures, to be noticeably less so. This is apples and oranges because I'm comparing the clincher CLX50 to the other 2 which are tubular, but net is comfort is as good as the Bora 35s, which I think are great.
7. Their weak point: their braking is pretty bad. Can you stop? Yes! But if the Bora 35s are really good for carbon rims (and decent in the wet, too) and the Zipp 303s OK in the dry (though scary as all heck in the rain - like - the hills of San Francisco are just downright dangerous on them), these are substantially worse in the dry and I don't yet know in the wet. Why worse? The front wheel gets hot fast and then starts squealing. The rear wheel, when braking with more than about 40% force, has been vibrating really strongly, which is then sent through the frame. It's terrible. I tried a bunch of different pads and moved the positioning of the brake shoes around a bunch. Tried clamping the QR very tight. But nothing worked. I sent it in to the bike shop today. They believe they've fixed it - primarily by swapping my Tune AC14 QR for a steel QR. Of course, I can run the Boras, Zipps and HEDs in the Baum without any problem with the AC14. I haven't yet picked it up to verify the QR change fixed the problem. Net: even if the rear wheel issue gets fixed, still substantially worse on the braking front than Boras or Zipp Firecrests. Of course, keep in mind, I'm comparing these CLINCHER CLX50s to TUBULAR 303 Firecrests and Bora 35s. It's possible I'd feel different if I had experience on the clincher versions of those wheels.
Net: the braking sucks, but I *love* everything else about these wheels. Comfortable. Fast. Stable. Confidence inspiring. No crosswind issues. I'm really impressed. I just wish they were 1 gen later on the braking front.