I suspect the reviewers who gave this item just the one star, work for competitors to Polar because personally I am seriously impressed.
Lightweight and stylish and always attracts positive comments.
I use it not only for everyday wear but in the gym for strength training and aerobic activities such as rowing and running.
You can customise the training for your needs via the website and train against that, or you can set it to whatever type of training you're currently doing and monitor and record your progress. It even tells you when to start your next set.
The chest strap is comfortable and I am not aware of it even when playing tennis. The batteries can be replaced in both watch and strap by yourself now, but I've had it for 4 months and there's no sign of any battery problem. I honestly expect it to last at least 12-18 months like my other F60.
I have two minor issues with the watch however. Firstly the buckle side of the strap is significantly shorter that the 'holey' side which means the watch swivels round my wrist so that the buckle defaults to the middle. This means the watch also swivels accordingly and sits slightly off-centre on the outer side of the arm. I like to wear my watches loose and I have big wrists so maybe that's just me.
Secondly, the 'return' button on the lower left side is hard to push in. I suspect that it may be part of the design to prevent accidental resets, in any case, it's not a bother, just not so easy to press the button in.
Other than that, it's an excellent purchase. If you shop around it can be purchased for under the £200 mark.
ps. I just got the trophy avatar on the watch for a good week's training!