Personal experience. I didn't want to change to type faster, but to feel better. After some carpal pain, I decided to switch, and the important result is that typing now feels effortless. I could not properly touch type in qwerty. I could type without looking at my keyboard, but it was not real touch typing, and the difference, after learning properly, shows
My girlfriend jokes that now when I start typing I behave like a pianist, carefully laying down my hands in the correct places. And it indeed feels that way, when I start typing is now my concert, where before switching to colemak (which makes movement more fluid, really) it felt like a cat hitting a piano.
Now I type faster than before, if I want, but speed is rarely my issue. If I'm doing something hard, I can't think faster than I can type. And if I'm doing something easy, I could type fast enough before already.