I think the best argument for things other than QWERTY nowadays is ergonomics, not speed. RSI is no joke.
FYI I didn't switch off of Dvorak because I was bored of it, I'd traded my left hand pain for right hand pain, and I decided it was a bit worse. Workman is more evenly split between hands where both qwerty and Dvorak had a major bias.
Workman also seems to beat Dvorak and Colemak in efficiency, but if that were my main concern, I also considered qgmlwb and Halmak, which IIRC are even better.