In my case, there are no complaints about the filling yet - not even a year has passed. But the shape, weight and materials are not balanced. The shape according to the photo is similar to mice already familiar to me, but the highest point is shifted back and, as a result, 2-4 mm of mouse height is missing - the hand slides. Light weight with such a grip and a sliding hand leads to a loss of control, the sidewalls made of ordinary plastic do not give additional control, you automatically move your hand forward relative to the center of the mouse and it becomes inconvenient to use the side keys. The hand is male average, I like and used Zowie EC2, Logi G403, perhaps my review will be useful to similar buyers.