I have three of these now and like how easy they are to set up and use.  After calibrating with the bike tire size, the unit seems to be very accurate when compared to my Car's odometer.  Battery lasts a long time.  I worry about the display falling out of the bike mounting bracket.  It wouldn't take too much to accidently knock it loose.  For this reason I put a little dab of hot melt glue on the side of the display and mounting bracket.