Sometimes I like a camera lens that is considered a little less than "perfect". A a great example in my camera arsenal is the 80mm lens on my Mamiya C330 TLR. Throughout most of its aperture settings it is tack sharp and nearly flawless but when set wide open at f/2.8 the quality degrades quite a bit in the most spectacular way.
Not only is the overall image a bit on the soft side, a quality that I think works nicely when photographing the figure with some old school black and white film, but more importantly, the bokeh (out of focus area in the frame) has a kind of circular quality. In a square frame this works so well to bring the eye to the subject in an oh so subtle way.
I always find it interesting when photographers shell out big bucks for cameras and lenses that are rated as "the best" on paper. Perfect lenses don't always make perfect photographs.