Very Finicky: Takes Practice, and Needs a Perfect Surface
First off, the Snap Jack can do what it advertises; prop your rear tire off the ground via lifting the right side of the swing arm. However, it is very finicky in that everything has to be just right to work: proper angle, firm rough surface, and flat shape of lower swing arm. If any of those factors aren't good enough, utilizing the jack can become problematic. Proper angle can be dealt with via practice, but swing arm shape can be a tougher problem, especially if the bottom of the swing arm is at a steep angle in relation to the ground. Firmness and smoothness of the ground is the real limiting factor to the Snap Jack.
I have a '17 Ninja 1000, and the SJ works well in my concrete drive way. However, in my garage where the concrete has a smooth finish, it doesn't work at all due to the Jack sliding on the floor. Further, when traveling it also has issues with gravel and dirt surfaces.
If your purchasing this for travel, and you typically stay in Hotels/Motels (with paved parking), this can be a good option. You do want to practice with it before using it. If, however, you are a camping or staying places without a paved surface, you will definitely want a different solution.
Because it is a bit finicky, and is limited to hard, rough surfaces, I don't recommend this product. I've had better luck with roller type wheel stands.