Polar HRM's

I'm not sure what the others have, for sure. I know the more expensive models will not interfere with other HRM and machines at the gym.

I have had an F4 for two years, and I love it. It does what I need and want: tracks my HR through workouts and tells me calories burned. The only thing I wish it had was a light for when I have run outside in the early morning before light. (which really isn't an issue lately).

Enjoy!!

the F6 includes the ability to link to the polar website where you can track and do other stuff like create a personal workout schedule. I think the F11 includes a fitness test right on the HRM, the F6 has the ability to do a test to get your target heart rate range based on your heart rate while doing certain tasks - the instructions are in the booklet but I haven't tried it, I only got my F6 yesterday. (I was actually going to make a post of my own about that when I saw this thread). Makes a big difference! The only other difference I can think of is that the F6 transmission signal is coded so if you're in close proximity to someone else wearing a HRM the signals won't get mixed up. I think a lot of people here have F4's and they seem to love them though so I think you'll be happy.

Good luck, happy exercising!