Polar RCX3 or RCX5 are pretty good models. With select athletes we also use a Polar app (for iPhone) coupled with a Bluetooth Polar strap. This way all of the training data uploads automatically to the www.PolarPersonalTrainer.com.
We don’t have much experience with other brands. The best part about Polar, – it’s their training logging software. Very comprehensive for coaches/athletes to review and plan training. Our coaches use it for keeping track of their athletes’ activity. You can enter workout info manually, – in other words it’s not mandatory to use Polar products to make use of the system.
Hope this helps!