I am very happy with my Polar CS500. Gives me reliable hrm, cadence and speed data. Everything wireless. I train often in the evening under high tension power lines, with a LED lamp next to the computer and haven't noticed any interference problems. The display is nice, large and very easy to read. If it only had illumination it would be 100% perfect. Still, even in dim conditions the numbers are large enough to be recognized.

In the beginning when I bought it I had a couple of issues that are now solved. Firstly, for the IR data transmission you need to upgrade the software to the newest level. In addition, for the transmission to work perfectly, I found it was better to exit the internet browser, since the Polar wants to open it again itself to get you to the online training analysis webpage. Secondly, it is important to pre-wet the hrm belt to get reliable readings from the very first minute. Both of these were minor issues for me and do not bother me any longer. All in all, I'd recommend it to a friend (but one has to know the limitations for riding in total darkness) ;-)