New Bridgepoint Hospital -- NEX-5N & Rodenstock Rogonar-S 90mm f4.5. click for larger
At one point I was crazy about making enlarging lenses to fit my Canon cameras. There were some success and I have had accumulated a lot of enlarging lenses in the process, mostly 80mm-150mm. The biggest challenge, aside from making them usable on a digital camera, is the lens flare. Flare could reduce sharpness and contrast and in some severe cases, makes the middle of the picture brighter than the rest. There are work around of course, but it's such a pain, because the front of the lens normally do not take filters, making it difficult to add a lens hood.
My experience with enlarging lenses is that they are mostly very sharp, at least at close range, but at the same time, much slower than most normal lenses at the same focal length. They do make excellent macro lenses with extension tubes, and they are very well corrected. Image quality is very good and usually better than the zoom lenses with uniform sharpness when stopped down slightly.
If you like tinkering, it's well worth the time. They are still dirt cheap so it doesn't hurt too much even it the lens is destroyed or not working well.