Summary: First off I would like to say the sensor on this mouse is top notch. I felt the type of control I had in the mx518 days. Which is why I was super dissapointed with the side buttons and discomfort. The side buttons were already faulty and would often not do anything. On top of that, the way they lay and flush made it easy to hit both on accident. Additionally the finger rest on the right side turned out making this a hand cramping nightmare for me.
Summary: I bought this mouse because many places rated it highly for the claw grip style. Unfortunately despite having what I consider normal hand size, I found this mouse way too small for my claw grip. It feels more like a fingertip grip mouse to me, made to keep the palm completely off the mouse. I did not find this comfortable at all. In addition to the small size I found the build quality to be average at best.
Summary: 4 star Overall I love this mouse, all the positive things in other reviews are true. If you like claw style mouses, then this is a bargain. - 1 star Durability proved to be an issue. However, at about the 3 month mark one of my DPI switches broke. I was then stuck in the lowest setting. When I went to check my warranty online I noticed that the serial number on the bottom of the mouse had partially rubbed off.