Polar CS200cad
I ride to a specific heart rate - as instructed - my cardiologist is a triathlete - then I select a gear to give me a cadence of 90 to 100 (at that HR). I don't care what speed I get.
Each ride is logged and over the months I can see the changes in ave. speed as a rough measure of performance improvement (or otherwise!!). Seems to work ok. I am feeling stronger and getting faster, all within the same HR limits.
The only time I take an interest in the speed is downhill when I exceed the posted speed limit - it's an ego thing!!