I've had two Polar HRMs (one was an upgrade) as well and can't say I'd recommend Polar to anyone. I use my HRM mostly for cardio at the gym and the Polar models are notorious for picking up cross signals.

But I do suggest that you return your Polar HRMs to Polar for repair. I did that with both of them and Polar repaired them at no charge even though they were out of warranty.

If nothing else, you'll have a backup HRM!