I’ve used the dual gripper Novagrade. It was pretty good, but finicky and not something you pop your phone in/out quickly.
I also tried the Carson adapter. Junk.
My use is hunting and filming funny prairie dog hits. I want to be able to pop my phone in and out fast to allow others to film (and for me to use my ballistic software) plus I move around a lot.
My light testing so far suggests it’s a superior unit. But I haven’t used it in field conditions. The case is good. The part that fits around the spotter eyepiece is all aluminum and really nice and turns smoothly.
It’s better thought out and better constructed than the Novagrade. It’s not cheap.