It goes without saying that to get the most out of this ergonomic mouse, your work space needs to be ergonomically setup. I bought this mouse along with an ergonomic keyboard and keyboard desk tray without considering how they would all fit together - they don't. To be effective, I think this mouse needs to sit close to your body so that your arm isn't stretching out too far. The keyboard tray I bought doesn't allow for this, so instead of wrist pains, I'd have discomforts in my elbow and shoulder after using this mouse for long periods. When I know I'll be doing a lot of mouse work, I'll move my keyboard to the side (its size is the reason the mouse is sitting so far away) and can work comfortably. Ideally, this mouse would sit on its own shelf that could swivel to keep my elbow close to my body. I've also used it on the desk top (it arrived before the keyboard shelf) and that is equally uncomfortable and worse than a regular mouse as it requires your arm rest unnaturally on the side of your wrist. It does take some getting used it - I've had to make an effort to grasp it completely. It's easy to click and move without putting the whole mouse in your hand, and that can lead to pains at the top of your hand and fingers. All that being said, I do think this is a great mouse. It is slick, comfortable and easy to use, so long as you're using it correctly. One more thing - it is taller than a regular mouse and therefore requires more clearance under your desk on the keyboard tray. Just another thing to consider when planning out your work space.