They were one of the very best (and fastest) lenses of their day, but are all around 60 years old now, so performance will likely be very condition-dependent.
Mine's in good order. It's sharp enough from about f2.8 and very sharp from around f5.6. It gives quite high contrast, but not as much as an optic with modern multi-coatings. I don't care much about "bokeh", but at the widest apertures I've never found this distracting or unappealing.
With colour film the results are distinctly too warm for my taste, but with black and white it draws very well and has its own character.
In general, it's a great lens. Sorry I don't know of where you might find a proper review though--Google might assist?