Sigma Sport's PC-800 displays your current pulse as well as a clock, stopwatch, date, alarm clock, upper/lower limits (with audio alarm for out-of-zone warnings), and displays your total training times inside and outside of those limits.
Weaknesses: Inconsistent, unreliable, bad reception
This thing has been flaky from day one. The only time it works well is on hot days where you're really working up a sweat. On training rides on cool days it maybe works 10% of the time. Then again on a hot race day or in the gym it will work close to 100% of the time. Get anywhere near power lines and reception gets screwed up. It was extremely frustrating to use. Finally I broke down and spent $400 on a Polar system - omg what a difference ! So if you live on the equator, or like to slather your chest with conductive gel, you might enjoy the PC800. Otherwise if you want consistency and accuracy in a HRM, steer clear.