I've got a Garmin Forerunner 205, and have logged over 10,000 miles on it. I absolutely love it. But I'll soon be wearing a Forerunner 405cx, which will allow use of HRM and cadence sensor. For me, the key feature of a GPS is that in addition to being able see my speed and distance on my handlebars, when I get home I sync it with the computer and see a map, my speed at any given point, etc. and so forth. One big disadvantage of a GPS is that while they are a lot more accurate overall than one person in this thread seems to think, the speed displayed at any given moment is guaranteed to be a few seconds out of date. So if you're leading a paceline and need to maintain a dead level speed, a bike computer is essential. (I believe that the full cadence setup measures speed directly and shows that on the LCD, but I'm not 100% certain.)