And trying to remember how many laps of the pool you swam? Now you know your heart rate, cadence/stroke rate, speed, recovery and can download a map of your session with every detail plotted along it. You plug in and play to share with fans or coach and can get feedback and advice on what to do next and when. Training has never been as data rich and simple to follow. But then some fails, some gives too much info removing the human aspect, many are expensive and none can replace hard work. Save us the hard lessons - which watch have you found most useful, accurate, stylish, comfortable, affordable, serviceable and worth buying again?