Polar Heart Rate Monitor
I have compared mine to other ways of monitoring and I think it is actually fairly accurate. I was shocked to see how much I burned during a core and upper body work out! Even if it is 100-150 off, its still a huge motivator for me. I am now more addicted to that than I am the numbers on my scale!
Kat
I run also and I have found the Garmin monitor that came with my garmin gps watch the most accurate monitor. Polar was good but not as good. Garmin also lets me upload all my data to a computer so I can compare heart rate with speed elevation etc. It has really helped me maintain a good heart rate throughout my run