I use an HRM. I love it, but I use one with a chest strap. It doesn't feel any different than a bra strap - I find it to be very comfortable. Mine is a Polar brand, and I made sure that I bought one that counts calories - not all of them do. MFP's calorie counts are VERY wrong. I'm sure that even the HRM is not truly accurate, but at least it is consistent and you get to know how much to adjust.

You have to remember that you'd already be burning about 100 calories per hour, so if your HRM says that you burned 400 calories during a 1 hour workout, you don't want to eat an extra 400 calories. I cut off at least 100 calories from what the HRM says that I burned for every hour that I work out. Make sense?

Also, it's a good personal motivator. There are days that I'm just not into my workout and I'm thinking about other things, I'll look down at my HRM watch and see that I'm barely at the bottom of my target heart rate. So, I'll then force myself to kick it up a notch. It just helps keep me on my toes.

My step daughter has a Garmin, which also has a GPS in it and she loves it. If you are into running, this might be the right one for you. If not, the Polar might be the way to go. The folks on The Biggest Loser use BodyBugg, but I don't have any personal experience. One thing you'll notice when you go to buy one is, you'll see 6-8 models for each brand, all of varying prices. Of course they have different features and the more features, the more expensive. Of course, the calories counters aren't included an them until you starting hitting around $90-$100.

I hope this helps. I feel naked without my HRM when I work out, so I guess you can say that I love it.

I plan on using my HRM. I use my HRM for every workout that I do, and this will be no different. For some reason with this workout, I do not expect high calorie burns, but I know that I will be burning calories long after the workout is done. Will see how it goes.