I picked up the X Grip phone holder by Ram Mount last year at Iron Pony in Columbus. I wanted a solution to hold a GPS unit or my phone on the Ducati. After riding with it for 6 months I have mixed opinions.
I have only 2 real complaints. The first is that the grips sometimes hit the volume button my phone (Nexus 5) and that turns down the volume if I am not careful. There is no way Ram can do anything about that so, it is more of a personal issue I have to deal with. The second is that when I have my phone in the mount, the mount will rotate a little. My phone will turn 20 degrees or so. That is just because of the way the X Grip works. Again, not a big deal, just my OCD kicks in.
It is solidly built and mounted easily to the handle bars of my Ducati. Some people have complained about the rubber nubs coming off. I have not had that problem.
The only thing I have done is sometimes I wrap a rubber band around the phone & mount to give myself a little extra piece of mind.
Overall I am very pleased with it and would buy another one for my next bike.