For that, you get features like 4K video at 60 fps, HDR (a feature missing on the Hero 7 Black), 12-megapixel photos and very effective electronic stabilization. What's more, the Osmo Action 4K has similar resolutions and quality to the camera on DJI's Mavic drone, so it's easy to match up both cameras on the same project.
You can get the DJI Osmo Action 4K camera today only for $279 instead of $379, and by adding the code ENGADGETCAM at checkout, you'll get an extra $30 off -- bringing the final price to $249.
If you're looking for a gimbal instead, Wellbots has another good deal. You can grab DJI's Ronin-S (a larger and more rugged version of the Ronin-SC) for $629 instead of $749, a $120 discount. And by adding ENGADGETCAM code at discount, you'll again get another $30, bringing the price down to $599. DJI's popular gimbals aren't marked down this much very often, so if you're in the market, today's the day.