I would have to disagree, I had a sample Nikon and Rodenstock 150mm and decided to keep the Nikon, it seemed to have a little more "bite", at least to me . This is very subjective however , and samples can vary.
It seems to me that all 4 manufacturers modern 150mm offerings are probably so close in performance that other factors, (camera movement, film flatness, etc.) are going to affect your images before the (probably) minute differences between this modern MC glass.
Of course this is IMHO!!!
As I mentioned above, the Nikon folds nicely on the Shen-Hao (reversed) if that affects your descision at all- good luck! Maybe we can start a "Shen Hao user's group!

Matt