I use this mouse every day at work, and am very pleased with it. I'm a software engineer developing virtual environments, so accuracy and smoothness of motion can be very important.
The mouse glides very nicely on the tabletop, with no sticking or shuddering. The size and shape of it is excellent, making it comfortable and natural to use. The main buttons seem to have good sensitivity, so I don't need to press too hard, but I also don't end up pressing them accidentally. The software that comes with it is very useful as well for assigning specific functions or key combinations to the buttons, and it can automatically change profile to suit whatever program you're using at the time.
It's important to note that it's specifically shaped for an average-sized right hand. If you're left-handed, or your hands are a bit smaller than average, then it probably isn't the mouse for you.