For the price and feature set, the Karma Grip is the best gimbal available today for the HERO5 camera. Although they don't advertise this, it looks well made to be dust and somewhat water (maybe a light drizzle) resistant. You can mount the entire gimbal using the adapter ring to any standard GoPro mount (helmet, chest, bike, etc.). If you need this to be lightweight, the top gimbal can be removed from the lower handle and powered up with the optional Karma Grip Extension cable.
Once the HERO5 is docked into the Karma Grip, it will keep your GOPro charged. You recharge the Karma Grip by plugging it into the USB port under the handle. You can also connect to the Karma Grip's USB charge port (under handle) to download your GoPro footage, so you don't need to pull your SD Card out (but you need to download the GoPro Quik software to import). The Karma Grip compatibility with the GoPro HERO5 camera along with the price make this a must have accessory for HERO5 owners.
The new GoPro Karma Grip (Gimbal) is not available yet, and so I have to come up with a temporary way to fly my new GoPro HERO5 camera. The HERO5 is a much taller and wider design over the previous HERO3, HERO3+, HERO4 cameras and so most existing gimbals may not work.
For now my setup works, but for stabilizing handheld footage with the new GoPro HERO5, the new Karma Grip Handheld Gimbal is definitely what you should invest in. The Karma Grip interfaces with the HERO5, so it will power the camera and you can download footage by connecting directly to the Gimbal - no need to pull your HERO5 Off.