I don't know anyone nor ever seen an image taken by a Hassalblad lens so I can't comment. I don't know why that is.
Perhaps they are very expensive.
In Pentax world the lenses vary.
For example the Pentax 67 55mm F4 is a dog of a lens. Yet the 165mm F2.8 is gorgeous. Its fabulous wide open at F2.8 which is quite rare for a lens. The 300mm F4 EDIF is very good but expensive and somewhat rare.
I googled and found the same topic on Cloudy Nights:
http://www.cloudynights.com/ubbthrea...9/Main/5817054
Seems like they are made by Zeiss which usually means top notch. But as per the thread you need to evaluate a specific lens.
Greg.