I got a relatively cheap mount (that held my phone really well at first, but after a while my Galaxy Note 2 started going pretty nuts - lag, hanging, etc.

My friend highlighted it's probably due to the large amount of vibration (even though I was strictly riding on the road) that my phone was subjected to. I tried formatting the phone - something I was planning to do anyways - and it largely went back to normal. My friend helped me pad the clamp area with rubber matting to absorb the vibrations, and it kinda worked - though there was still a small amount of weird lag.