I have been using heart rate monitor since last one year. I have 2 heart rate monitors, one is omron and another polar, both purchased through KMD. I think, it is a must for people intend to do rigorous exercise/jogging with family history of heart problem. Your heart rate any point of time should not exceed a limit derived from general acceptable formula.
Omron with me is simplest, economical and good and polar is with many features but very costly.