Great GPS. I have several Garmins and this one's as good as if not better than the others. I also purchased the heart rate monitor and it works better than any other monitor I have tried. The only thing that would improve this GPS is a longer battery life. The 310 will go for about 18 - 20 hours which is not long enough for me to complete a 100 miler in the mountains. I run with the Wasatch Speed Goat Mountain Running team here in Utah.