> I would worry that with no physical presence on the keyboard, I would spend a lot more time looking at the keyboard figuring out where the function key I need is than actually getting things done.
Exactly. In Eclipse, F5 steps into a function call, F6 steps over it, F7 returns from the current function, and F8 resumes execution, and mistakenly pressing the adjacent key can be frustrating (although, with time-travel debuggers, this issue might be alleviated?).
Interestingly, when Lenovo did Thinkpad T430 series, they removed the spacing between the F-keys (in order to fit ESC in the same row). Such a tiny change, yet how much usability it destroyed - suddenly it was impossible to use F-keys by touch.
With T440, the spacing was back.
I would worry that with no physical presence on the keyboard, I would spend a lot more time looking at the keyboard figuring out where the function key I need is than actually getting things done.
I would be keen to see a review from somebody who uses the new Macbook Pro professionally as a developer to see if this is as much of an issue as I imagine it to be.