In reply to abr1966:
Just to add a bit of contrast to the Suunto arguement, I had an Ambit Peak3 HR and had a number of problems with it and lost data whilst training for races. Whilst I know its not the Suunto 5 it kind of sealed my opinion on the direction they were going compared with Garmin and Polar.
This resulted in me going to Garmin and never losing anything and I think a much better quality and app etc. Garmin connect gives you just as much if not more than strava, so ive stopped using Strava now.
The Fenix 3HR is a good starting point if money is tight on ebay for about 100 quid, or if you are a bit more keen to spend the Forerunner 945 is essentially a Fenix 6 in a smaller case.
Polar wise I have never had one but friends who use them like them.
Post edited at 10:21