I wonder why you did not just hire or borrow a Nikon kit just for a taste, and for making side-by-side comparisons with your established Minolta kit.

Another issue worth comtemplating is your desire to go for Nikon for its reputation. Now, reputation is a funny thing that tends to go before the name, and of course it is based on other people's criteria on what makes something "good". For me, I do not like the Nikon lenses for the "look" of their images; having been brought up on Teutonic glassware notwithstanding, I do not feel the bokeh offered by Nikon to my taste at all, and actually prefer Minolta glass for its more pleasant look.

But as usual, YMMV; pay your money and take your ride; good luck!