epatsellis, does it work that well stopped down? If so, I'm impressed. Again, I use to be of the 'lens defects are less of a big deal than people think' camp until picking up a few lenses with a bunch of cleaning marks which had extremely poor contrast to the point of being usable for the shots I wanted to get.
The impact on the negatives changes defect to defect. Without the ability to test it and be sure I understand what impact there is if any, I personally wouldn't be comfortable putting down a bunch of money on something blind unless I was confident I could sell it for the same price if it didn't work for me.
Thats just me though. Everyone will have their own criteria.