I have had this unit now for about 2 years after owning the Garmin 205 for about the same time frame. I run ultramarathons and when I wear a watch, this is it. I can honestly say that I only have one issue with it and that is the battery life. Just remember that you will need to be diligent about turning the unit off after you use it, otherwise you start your next run, bike, snowshoe, etc...with a low or dead battery (it does charge quickly though). I seem to get 18-20 hours of watch time before it will need another charge.
Battery aside...this is an all out great gps watch. I don't have issue picking up signals under tree cover, I use the elevation, Heart Rate, Virtual Partner, back to start, pace, laps, and the wireless upload to Garmin connect as well as the training software. I've swam with it, cycle with it, and run in various parts of the country and it always works. I've used it to set/measure running events as well. There literally are more features on here than you probably could truly utilize, but with all these features you are able to customize the multiple screens, watch/gps settings etc.
Bottom line is that it's simply a very powerful & durable training tool.