Summary: With enough practice, this trackball will reward your time and effort. If you want an ergonomic input device, this is what you want.
Pros: Extremely comfortable, Extremely forgiving for beginners, yet highly rewarding for veteran trackball users, Long battery life, Great looks, Lightweight design, Storage built into the battery compartment for the Unifying dongle
Cons: Right handed device only, Learning curve can be daunting for first time trackball users, Slick surface too slippery for smaller hands, Forward & Backward button locations does take some getting used to, Click wheel is loud and less than perfect compared to most Logitech mice
Excerpt: The Good Comfortable and precise. Good button placement. Very long battery life. Power switch and stowable Unifying Receiver. Easily programmable. The Bad No horizontal scroll or free-spin mode. Noisy. Ergonomics and precision feel Veteran trackball owners will find the M570's shape very familiar. Logitech makes this clear that it was on purpose: even on its promo page, the company showed that the design is a dead ringer in many ways for models several years old or more.
Pros: Comfortable and precise., Good button placement., Very long battery life., Power switch and stowable Unifying Receiver., Easily programmable.
Cons: No horizontal scroll or free-spin mode., Noisy.