The Tamron should be pretty good can’t wait to see a review here
Both of them let you choose Pentax, Sony, Canon and Nikon, but it seems in the CL review that the Nikkor lens is the better choice of current tested Tamron and Sigmas.
Still I wouldn’t prefer such lens alone since it’s not fast enough for lowlight situations (f3.5-5.6). I would probably also get a prime for those extra sharp portraits that at the same time is very fast (f2.8 or less).
Regarding body; I can only say that I am very satified with the ergonomics, manual control and most important of all in-body antishake of my Minolta 5D (which is now the smaller/older model of Sone A100).