The Razer Lachesis failed on many counts.
- Its buttons are still annoying to reach.
- Buttons 4/5 are both on the thumb side.
- Buttons 6/7 on the right do not work under Linux.
- The sensitivity is so outrageous I'd have to tone it down a lot, and even then it would reset every suspend/wakeup or reboot. Even with fiddling with its settings and my system's mouse settings it never felt right.
- It has a fucking night light built in. Although this can be disabled, one has to install Windows to do so.