I think Jack got a dodgy one.....
I got out of Hasselblad for several reasons mainly attitude/arrogance and who wants their closed system..? Anyway I bought into Mamiya because of their history and their open platform, they work hand in hand with both Phase One, Leaf and their own backs.
So, before buying loads of lenses I bought a couple of wides to try out, they were 55mm and 45mm manual 'N' versions, cheap as chips on ebay. I use a 22mp back with a 1.1 crop factor, so I shot both film and digital and the 45mm was spot on. The 55mm is known to be good and straight as it was the widest without needing compromises, several people have mentioned dodgy corners on older 45's hence my test.
Jack, go and rent one if you can and test side by side, you may be suprised. i have no hesitation in buying a new or newer 45mm AF or AFD now.
Same with the 150mm, several people have said it's a bit soft, others that it's spot on, my $275 EX+ model is again spot on.
Jack, is your lens dusty inside...? It took me ages to learn to 'see' inside a lens but I have seen a few with quite a bit of dust and fibers on the elements.
Just my 2c.
Steve