Just like any gadget, you learn how to use all the functions on this watch by just playing around and pressing buttons. True, the manual should be clearer, and seems to be talking about doing things in a different order than what's really needed sometimes, but unfortunately that's the case with most electronics these days. It's really not all that hard to figure out, and anyway that's part of the fun of getting a new gadget (for some of us, anyway).
It has worked pretty well since I got it. Took a few trials to get the strap tight enough so it wouldn't slide down while running. About 1/4 mile into my first 5k wearing it that's exactly what happened, and my grand plan of closely monitoring my performance went up in smoke. I've had no problems with the receiver picking up my heart rate, or interference from power lines or cars.
So, all in all, highly recommended. I think it's got just the right level of functionality for me, someone who wants to train with a monitor to get a little faster running 5k's and 10k's, but it also makes running a little more interesting on those days you just don't feel like doing it. 5 stars

I tried several other brands before came back to purchase this excellent HRM. I had an old Polar that displays only heart rate, more than 10 yrs old and still works, but I thought I want a little bit more.
The RS100 has a very good transmission range, unlike others that I couldn't even put it on my bike's handle bar. HRM functions are super simple, you don't need a degree in engineering to learn how to use it. The watch function is adequate. It is also a good looking watch, so you can use it for more than just working out. Buy it, you'll love it.

12/2/07: I am waiting for Polar support to get back with me. I had a maddening problem with this HRM. In time mode, all of a sudden, the watch shows the Polar logo on the top line instead of day of week and date. I read the manual no less than 10 times and wasted hours but could not switch it back. In 2 days, if I don't get an answer, it goes back to Amazon. 5 stars

I am a running novice and had received advice from several more experienced runners to utilize a heart rate monitor for my training. I saw this model as a way for me to easily monitor my heart rate during training. It has been reliable and easy to use. I have even used it while swimming. I haven't used the computer upload feature yet. I recommend this product for other novices. 5 stars

A great device for fitness motivation for a newcomer. Before, when I was running and rowing it was difficult to be sure of progress, now I see that, for the same heart rate, I am, week on week, increasing my pace and distance. Highly recommneded.

On the downside: I was cautious and bought the entry level model. Now, I would probably go for a model with some of the extra features. The Polar personal trainer website is interesting, but not great. 5 stars

This heart rate monitor is my first, and is in the middle of my second marathon training season, and has gone with me to five half marathons. I bought it because of the dual timer. I started as a run walker and with two timers, it told me when to run and walk to take a walk break, and then got me back running again. I tuck the monitor underneath the bottom rim of my sports bra, and occasionally it slips down a bit, but mostly the elastic strap, not the actual monitor. I also used to have weird connection problems - out of the blue I would get impossibly readings. 95% of that has gone away since I got "buh bump," an electrode cream created by one of the makers of the polar watches.

I consider this watch an essential part of my running wardrobe. It always shows your heart rate, and you can toggle the top level of information including the time, calories, and other features. I follow my heart rate closely because I tend to push myself a bit much, and the beeping is a great reminder to slow down, as annoying as it is. I use all the manual features on it though as the fitness test or whatever it is to find out your minimum and maximum HR is lame.

I work out at 24 hour Fitness, and I was surprised to see that their machines are Polar machines, so I wear my monitor on the treadmills and there's lots of programs that I can use without having to hold the metal part of the machine. And what's cooler than knowing how many calories you burned/have to replace. ;-)

The only thing I wish this watch would have is the ability to store more than one run in the memory (though this was more important to me in the beginning), and that Polar was as good in their GPS line (like Garmin) as they are with the Heart Rate side. But I have to remind myself that the simplicity of running can be the best part, and my watch should reflect that. 5 stars