Polar continues to improve on its existing running watches with the new M430 tracker. It's an upgrade to the M400 in many subtle ways, including an improved accelerometer, longer battery life, and the inclusion of Polar's own optical heart-rate monitor. Although it's positioned as a runner's watch, you can do much more with the M430 thanks to Polar's sport profiles. But runners will appreciate the convenience of having an accelerometer that can handle indoor and outdoor activities well, an onboard heart-rate monitor, and a GPS that doesn't make you wait when you're ready to run now. While it has stiff competition in the TomTom Spark 3, Polar's device combines enough essential features to hold its own.
Although the M430 has all-day activity tracking features, its design is best suited for training sessions. It has that rounded-rectangular shape many other Polar devices have, featuring two left-side buttons for the screen backlight and navigating back, and three right-side buttons for scrolling up and down and selecting options on the display. Physical buttons are easier to use (and more accurate) than a touchscreen would be on a serious training device, so I don't mind having them on the M430. In fact, I would have preferred them on the TomTom Spark 3 instead of its awkward touchpad below the display.