I think you'll hear a lot of people like the iOtties. I've gone through a few phone holders, should have bought it first. We have the previous version iOttie One Touch in both our vehicles and they haven't popped off since I installed them well over a year ago. The pitfall being there will be a preserved circle in the protected UV spot. I also leave USB car chargers + mfi braided lightning cables inside.
The other thing is if I extend the arm out toward me, it tends to bounce more so I keep them retracted in, not a big deal as we use the bigger screen iPhones up there anyway.