Polar RS300X SD
Best for: Athletes who don’t need the added cost of a GPS
Details: Its easy setup, snug-fitting heart-rate monitor, and calorie counter impressed Lovato. But he found it tricky to manually calibrate Polar’s RS300X. (At first, it displayed a reading of 15 minutes per mile, when Lovato ran it in seven.) “And the large foot pod slapped against my laces as I ran,” he says. [$250; shoppolar.com]
Rating: 5 out of 10