I previously had a Quad Lock Handlebar/Stem Mount, which was great, apart from the difficulty of adjusting it flat/level on the stem. (I'd constantly be adjusting it to what I felt was flat, but wasn't.) The Out Front Mount V2 cures that: you can adjust it for rotation front-to-back and left to right, but it stays flat in relation to the handlebars and stem. Very easy to read the phone once you've positioned it correctly and then it doesn't move. Total confidence that it won't shift.
The only real downside for me is that you cannot adjust how far away from the handlebar (distance front to back) the phone sits, but that is unlikely to be a problem for most people, as it clears the stem area cleanly. For the OFM V2, mounting/removing the phone takes two hands (rather than one only with the H/S Mount), but it's just a minor adaptation. …more