There are always a lot of comments about ergonomics when the Magic Mouse is mentioned, but never a single citation. Been using one for 12+ years. The utility and ergonomics are great for me. The idea that something has to be shaped for a body part to be 'ergonomic' is pervasive, but I suspect it belongs with pseudoscientific claims such as using 10% of the brain.
Ergonomics is probably the wrong word to use but the magic mouse isn't a comfortable shape for most people. Less subjectively though it's sensor and tracking are terrible compared to modern sensors. All of this can be ignored for most typical work uses I suppose but what can't be ignored is the insanity of placing the charging port on the bottom of the mouse so you cant use it while charging.
Deadmau5 charging is a straight up swing and a miss but scrolling left and right hasn’t felt right on any other mouse on MacOS, and it’s something I seem to do a lot.
It's really short compared to other mice, even other ambidextrous ones. I can't really rest my hand on the magic mouse, it has to hover because of how short it is. This to me is uncomfortable long term. It also just has bad tracking and bad feet that make it bad to use.
I have big hands, the Magic Mouse is simply too small for me to hold naturally and quickly makes my hand cramp. I buy those things you stick to the sides to enlarge them, but they come unstuck within a couple of months.