Not an Edge user but I would agree that on my Etrex 30 (default settings) it is far too late with its turn warnings, especially at slow speeds such as cycling up hill, and yes occasionally I can reach a turn before the warning kicks in. On this model the 'off road transition' distance can be tweaked away from the default to add say 30 metres, which helps a bit though it's difficult to find the ideal solution for all speeds.