I am left handed and I use almost exclusively the left 2/3 of the space bar as it's easier to press it with my left thumb. Maybe I just taught myself the wrong way but I am competent at typing and this Microsoft's keyboard would be just unusable for me. I wonder how it goes for other left-handed people.
This is so true for me that there is a thumb-sized mark on my spacebar where the finish on the plastic is worn because I always press the key at the exact same place.
I am left handed
This is, of course, true for a lot of people. I think the solution is to do what the microsoft keyboard did, but provide a hardware switch to toggle which side is space.
But it also would be useless for gamers, as the left hand is over WSAD and the right hand having the mouse. Space is mapped to jump in many games (some of which you cannot remap), and you gotta jump sometimes.
Watching myself showed I'm using right hand's thumb almost always (like most people according to that article).