What do people make of these two gps units, looking for something I can use in the field as a backup and also for running, cycling kayaking etc. Was just wondering what everyone thinks, thanks. Foretrex 101 http://www.amazon.co.uk/dp/B000255I8W/?tag=armrumser-21 forerunner 101 http://www.amazon.co.uk/dp/B0001ILXGQ/?tag=armrumser-21 edit: not to fussed about the Heart rate monitor function as I already have a polar HRM, but was looking more at the gps function. Can these both give OS grids??