My hand span (as pictured below is something that you measure from the outside tip of your thumb to the outside tip of your little finger) is about 22 cm or 8.7 inches. Not especially huge, but big enough to make it difficult to find a mouse that adequately supports my hand and doesn't cause pain in my wrist and forearm, cramps on the back of my hand and numbness in my fingers.
I've spent the last three years using a Logitech M570 with its ergonomic trackball design. While the mouse works really well, size-wise, I've always disliked the slow speed and poor accuracy of rolling around that tiny blue ball in my thumb to get anywhere or do anything.
With the M570, finding and moving my cursor from the far side of one 27" monitor to the far side of another 27" monitor takes over six seconds.
Try it for yourself; how long does it take you to move a similar distance with a non-trackball mouse? For me it's about one second. Six seconds is quite comical.
In searching for a new mouse that's at least as big or bigger in size to the M570 but doesn't use a trackball, I've learned that the pickings are pretty slim.
First, there's the crazy freak show USB Big Mouse.
Or the Mad Catz R.A.T. 9, which is straight out of Battlestar Galactica:
I already bought and returned both the Razer Death Adder and the Razer Imperator because they were too short and flat. I'd read online that these mice are optimized for bigger hands, but in my experience, neither is ideal:
I also bought and have since returned a Hippus HandShoe Mouse which absolutely dwarfs the M570 (and even the Apple Magic Trackpad to an extent). Here, take a look; the HandShoe is on the left.
While I liked the proportions of the Hippus HandShoe - it's the only mouse I've ever tried that's even close to the size of my hand - its level of accuracy was not good enough for the detailed pixel work I often do. I also felt as if my hand was never really resting properly on the mouse even when I followed the instructions Hippus provided. The thumb pains I used to have went away, but new pains developed. For a $150 mouse, I feel like I require near-perfection.
So, my search continues. As I said, the Mad Catz R.A.T. 9 is still an option, but I'm also open to suggestions. If you're aware of a non-trackball, ergonomic mouse that fits big hands, please let me know.