Good:
- Sturdy mounting clamp, good grip. Easy to get reassuringly tight.
- The bar clamp does not seem excessively wide, so it is likely you will find a convenient spot on the bar to mount it.
- Holds Samsung S9+ phone (with case) extremely securely, even when not locked. I forgot to lock it several times, it made no practical difference.
- Lock gives extra reassurance; also some security if you leave the phone on the bike temporarily.
- Mount did not move at all, even on washboard gravel roads or highway speeds. I also do ATV, would not hesitate to use this on a quad. I don't do mountain biking, but IMHO it would be fine for that too.
- I never observed the phone moving inside the mount; zero cringe factor. Inspires high confidence, zero concerns about it ending up on the pavement.
- So far the mechanism shows no signs of having difficulty with road dust gumming up the works.
Bad:
- It was insanely difficult to attach the clamp to the mount. Measurements show that as designed, it is almost impossible to do so. This is hardly the first mount of this style I have assembled and most take 1 minute. This took 30 minutes of swearing and excessive force. See video; replay that 20x, that was my experience trying to assemble it. Vendor didn't have much to say about this issue. I wish I had known about the acetone trick mentioned in another review, as it might have helped.
- Once assembled, the lock ring between the clamp and mount never really loosens, and if you accidentally detach it you're in for another 30 minutes of swearing to get it back on. Meaning it is difficult or impossible to change the phone's position / orientation.
- Lock tab is ridiculously difficult to actuate, both locking and unlocking. It was so hard to move I took to wearing my riding gloves when shoving on it.
- One-handed mounting or removal is impossible, at least with larger phones, as the springs are too stiff for that. I needed two hands: one to push the phone up, one to pull one of the bottom clips down. So much for one-handed operation.
- Bottom mounts are so thick they interfere with a right-angle USB-C cable. I was able to get mine to fit in to the phone, but just barely.
Overall, it does the job of holding on very well, but is not well designed and fails on most of the "special" features that distinguish it from other similar mounts.
As with all mounts, you do have to take a bit of care that the phone is centered and the mount is tight around the phone.
If I had had time to return it before my trip I would have done so, as I think this product is just badly designed, and I was ready to smash it to bits because it wouldn't assemble. I didn't have that luxury.
I would have returned it after, but after my road trip it is dirty enough and worked well enough that I felt it wasn't appropriate. Plus it's already on my bike so I might as well continue to use it until it fails.
So, works great, but crap design and poor user experience. 3 stars overall.