I've had it for nearly a year and I LOVE IT!
Garmin Forerunner 920XT Tri Bundle
Having two heart rate bands means I can keep the backup in my gear bag. Thus when I forget to put the band in my gear bag after washing and drying in fresh water I still have a backup band.
If you want to save some money, get it with only one heart rate monitor band. As I type this today, Amazon has the red version on sale for $50 less than the blue one.
All are great and you can customize them for Windsurfing along with the standard settings for all three triathlon sports (run, swim and bike.)
Here is my screen to review my session to post on Facebook.
And this is the screen I watch while windsurfing to get my speed, time on the water and distance sailed.