That variant is based on the old version of Colemak, and based on countach's feedback I improved some things in Colemak.

That variant is maybe better in C according to countach, although I don't think so, the position of the braces is much less comfortable in that variant.
It's the same in literature, and it changes a lot more keys from QWERTY, and moves keys from hand to hand so it makes learning the layout much harder with very little benefit. Since the punctuation keys aren't typed often, it takes longer to learn these keys.

That variant is just to make it easier for people who are already used to Dvorak-style punctuation, and to demonstrate to countach that the Colemak layout isn't inherently flawed, but more of a result of the bias of his scoring method that benefits Dvorak-style punctuation over QWERTY-style punctuation.

In summary, I highly recommend sticking to the standard Colemak layout. If you do decide anyway to use a variant, I recommend the one that I suggest at the bottom of that thread.