Are cheap chest straps like Coospo as accurate as a Polar H10?

For steady-state cardio, the consensus on r/Polarfitness, r/concept2 and r/Garmin is that the Coospo H808S and H6 are surprisingly close to the H10 — some long-term users actually prefer them. Where the H10 still pulls ahead is HRV measurement, internal workout memory, and the strap's longevity. For most recreational athletes, the gap is small.