I've worn a Garmin Chest Strap HR Monitor for four years. It came with my Garmin 1000. I've never physically been bothered by it or for that matter even noticed it when I've ridden the X thousand of miles with it. Besides comfort and convenience it records up to 10 meters from the Garmin 1000 computer it's paired with. The batteries last a long time and are cheap at about five or six dollars apiece.
The latest model of the chest strap can be paired not only with the computer but with your Smartphone too.