The Roccat Kova[+] is a 7-button (another +2 for scroll up and down) configurable mouse. The software allows each button to be customized. Together with their trademark EasyShift[+] functionality, the Kova[+] allows up to 16 different button functionalities at any one time with 1 dedicated "shift"...
Configurations takes over 40 seconds to apply; Unable to customize weight; Hard to clean dust off and keeps finger smudges; Auxiliary buttons are not shaped ideally and offers too much resistance for critical macros