Garmin 500 vs Polar CS200

simmo3801

On returning to cycling I thought I'd get a GPS computer as I thought they looked neat on the stem without additional sensors on wheels, forks or stays. Now I've seen the price and read some reviews of the Garmin 500 I'm wondering if I'd be just as well getting the Polar CS200 for half the price. Both come with HRM and cadence sensor. The reviews I've read seem to involve the GPS working accurately so people are using a speed sensor anyway. The route guide I don't think would be used personally as I generally know where I'm going. My only issue I think is I'll be using a turbo trainer as well and therefore the Polar wouldn't record speed on the rear wheel whereas the Garmin 500 would. Am I missing anything????