I have worn a Fitbit HR Charge for a couple of years now. These days I mainly use it for the sleep tracking feature, and I pay a little attention to steps. I run 5 miles, 5-6 days a week. I use a Garmin ForeRunner to track all of my running data. If you end up running on a regular basis, I would highly recommend getting one. Provides more data than I thought was possible.
FWIW, I find that the heart rate measured by the fitbit to be approx 10% lower than readings from a Heart Rate strap, or pulse oximeter while I am running.