Uses Kensington's trackballs, which cost as much as this, but Kensington has significantly better quality. This, however, has a thumb-ball which I think is more comfortable.
Like all trackballs I tested this works for easier everyday tasks, but should you draw in CAD or anything that requires precision does not work trackballs. Precision comparable to Logitech M570 but clearly worse than Kensington. (380 DPI according to the manufacturer, currently writing 440 DPI.)
* Wireless but it has a USB cable that connects to the computer, which only charges the battery. It can not be controlled from the computer with the cord even though it is in the computer. It connects with a separate wireless USB dongle, so this mouse takes up two USB outputs. Unbelievably corked!
* The supplied USB dongle has very short range (about one meter) so the computer must be close to the mouse if you do not connect with bluetooth.
* The mouse is new but the quality usually is average-good on Logitech stuff, this "feels" the same way.
* Magnet-mounted tilt plate, keep your mouse away from bank card speakers and other things that can be affected. Corked design again.
* "8 buttons" includes the ON / OFF button. Wireless Sync Button and "Advanced Scan and Precision Mode Button". In practice, it has five buttons, two regular clicks, the mouse wheel and two programmable.
* "Advanced Scan and Precision Mode Button" does not make precision better, only the mouse slows down a bit. = p
* 900 kr for this mouse is long above what it's worth to pay for. Can not compete with Kensington regarding quality and ergonomics in this price range.
* Relieves the correctly used wrist, elbow and shoulder. But do not finger your finger.
* Comfortable and ergonomic to fit in. Much better designed than before M570. This is shaped to fit in one hand. (M570 bumps the wrist and seems to be designed with an oergonomic grip)
* Battery life seems really good.
Recommendation: Buy if you can get it for about 300 seconds and your computer has bluetooth. Otherwise, choose this and M570.