Are the Tomtom proprietary hr sensors just as good as the Mio versions
I recently picked up a Runner cardio on ebay with the Mio hr sensor and very impressed with accuracy and the watch in general. I use it for cycling even though it doesn't have a cycle specific function but the GPS data is the same anyway. If I chose to get the Spark 3 is there any difference between Tomtom's own sensor and the Mio. I've noticed a lot of refurbs on Ebay.