I've been using this for about 3 weeks and it's noticeably better than my old 'vertical' mouse for wrist pain. The difference is that the penguin is a lot more vertical - my wrist is almost totally upright and straight while using it, while my old mouse (an Anker) was more like 45°. The battery is also very good so far - I haven't needed to re-charge it since the day I got it. My only complaints are that I couldn't try out the different sizes before buying it (I need Large according to the size chart but have to lift my forefinger up to reach the button, so think Medium may have fitted me better) and it's a bit overly expensive.