I purchased this mouse over the weekend, and I've had a few days to get use to it. I like it a lot.
It's high resolution, so the cursor movement is smooth and precise. It's a little larger than a normal mouse. That's good for my large mitts; but it could be better. It is a good shape that fits into my palm, and my pointing finger and middle finger rest comfortably on the left and right mouse buttons.
The mouse wheel has variable friction. This took a little getting used to. When you move the wheel slowly, it feels like it's filled with grease. When you move the wheel quickly, it feels fast like oil. this is good because the drivers that come with the mouse enable accelerated scrolling. That means that the faster you move the wheel the faster it scrolls. Move the mouse slow, and the document slowly scrolls; but zip the wheel, and you'll instantly reach the bottom of the web page. I wish all mouse wheels behaved this way.
The wheel also has tilt. I don't find myself using this much. I'm thinking of remapping the tilt to some other function - like back and forward in the web browser.
The mouse has fourth and fifth buttons above the thumb. By default, one is programmed to go backward within the browser, and the other activates a magnify function. The magnify function is useless for me, and I'll reprogram it to do something else when I think of something good for it to do.
I recommend it.