I had an Edge 305 for cycling and it lasted 3 years, my hubby's has lasted almost 4. Now have a 310xt and love it. I bought the fast switch strap so I can easily switch it from wrist to bike. The old Edge I had to carry in my hand. And the 310xt shows run pace as well as bike speed. The Edge didn't show me run pace, only miles per hour. If you're not a triathlete then you probably don't care that you can wear the HRM strap in water which is nice for a race.
The wrist band and the run pace option are the two main advantages of the 310 over the Edge.
