This mouse is built for people with long fingers, of this I have no doubt. The masses of mice that I've left in my wake have all been far too short. Not quite the iMac circle mouse, but not too far off from that. With the Mx518 my orangutan-like hand rests regally upon my mouse, like a king on his horse. Of course, it is also functional for those with normal-sized hands.
The mouse curves in slightly where the thumb normally rests, creating a comfirtable grabbing posture with your fingers. Above the thumb are two buttons, and when I say "above", I mean directly above. Which creates a slight problem as even slightly bumping the largest button with a back arrow on it will cause most browers to go to the last page. This would normally be a helpful feature except that I bump this button far too often, in fact I hit it while I was writing version one of this review, causing me to have to start over. This button is a benefit and a curse, as those of you who play computer games often will no doubt find the twitchy extra button quite useful. There are three other buttons that most people will never use in their entire life. One of them is a faux task manager, the problem is that it is placed exactly where the middle finger frequently presses it, causing an ugly task manager to pop-up. This is easily solved by simply closing the mouse software. The two other buttons are located to the front and back of the scroll wheel (which is perfect, the amount of resistance is spot-on), these buttons increase the sensitivity of the mouse. Meaning that if you press the + button the mouse will careen to the corner of your screen when you stare at your mouse too strongly. The - button similarly causes your button to become as unresponsive as a snake in a freezer. I would suggest never touching those three buttons, unless you are some sort of hyper-professional gamer.
All in all, using this mouse is one step below wrapping a gold mouse in silk and using that, just as long as you don't mind a few button issules.