I also see the HD recommended a lot, but not too many mentions of the white #2, which is the one I am more interested in. J's measurements on his site have the carbon thinner than the semi or full stainless I believe.
I have both, and the differences, as Jon has stated, are nonexistent. The HD has a slightly different handle, and, being semi-stainless, doesn't have any reactivity issues which the white #2 does. Of course the HD doesn't patina like the white #2, if that's important to you.
The HD, as has been reported elsewhere, does have better edge retention. Sharpening either knife is a breeze.
My recommendation is the HD, unless the price difference is a dealbreaker.