Just wanted to chime in with my experiences with the mouse. I never had any RSI since last winter. Basically my whole life I used some sort of ergo-like, lightweight large gaming mice. Sometimes very cheap ones. But on my new workspace I got a quality, yet slightly uncomfortable wireless mouse, medium sized so it can be carried around. Few months later I developed a strange pain which was going away during the weekend. Long story short, i reluctantly borrowed, later buyes, a Logitech MX Master mouse, and it all went away. I use it still. I say reluctantly because of all my gaming mice I perceived this one as heavy and sluggish. But I've got to hand it to it, after hours of using it, there is no fatigue in the wrist or arm.