They are loud, to the point of being annoying during a meeting / conference call and the travel distance is a bit too short for some people, making typing unpleasant. If you use a Lenovo or even a dell of equal body thickness for a bit and then get back to a modern Mac, the difference is huge.

Failure rate, not typing speed, is the crux of the concern. Additionally, at least for me, is the volume of the keypresses - much louder.

The two main issues for me are failure rates and key travel. My fingers literally hurt when I use it. The 2012-2015 form was probably less beautiful to look at (and slightly thicker), but it was much better to type with.

I'm glad someone else mentioned their fingers physically hurting when using it. I haven't seen many other complaints round this online and its shocking - This made me stop using the device completely - I was in pain just by typing normally!

I didn’t get it until I bought a new keyboard and starting working on it. You quickly realize how uncomfortable this keyboard is.