This sports bra is a great idea, nice thought to bypass the strap.  And it does work well, after Im able to fight the thing onto my body.  It's got a back clasp, which is hard to hook, because the built in strap very very tight, with little elasticicty or give.  I'd recommend ordering one  size up to accommodate the strap fit, but am not sure how that would affect the fit of the bra elsewhere.  Aside from the tight strap, it fits me perfectly.  I should mention that I'm a very petite female.

For the price, I'd pass and check out either the Under Armor or Road Runner Sports' brand, and just continue wearing the Polar strap separately.