As much as I loved my Garmin Forerunner 405 watch I knew it wouldn't keep up with my evolving training schedule. The main problem is that the battery would die after four hours of use, which is fine for being a running watch, but my rides are gradually getting longer and longer. I picked up a new Garmin Edge 500 mainly so that I could sync it with my new Powertap G3 as well as make use of its long-lasting battery.
It does everything my 405 did and more. Making use of Garmin Connect's Courses feature, which by the way got a serious makeover recently, made mapping new routes a breeze. You can then upload it to the Edge 500 and follow the pre-plotted course. It's still a little buggy, but works fairly well. I also use the Workout feature and uploaded those to the Edge.
Besides that the Edge 500 is nice and light, and not too overbearing in size. The mount is simple and secure. The unit itself is weather resistant, but I don't like how hard the buttons are to push. The display is decent and has a number of options for how much data you want to see at any given moment.
I'm now fully hooked up; a heart rate monitor, a cadence meter, and now a power meter. It feels odd to be so connected to your bike, but it's almost become second nature by now. Learning how to associate the numbers I produce to how it really feels will be an important tool in the future. Right now I have a good understanding of my heart rate zones and cadence, but I'm still getting a feel for wattage and power zones.