People sometimes worry about the sharpness of a lens and then upload their pictures to social media where it is impossible to tell how sharp a lens is. Other factors like bokeh, contrast, colour etc are easily visible even at smaller resolutions on social media. Because of this I think that the overall rendering of a lens and its creative imperfections are more important than its sharpness. I wouldn’t say that old lenses have better character than new ones since this is all a matter of personal taste and lens designers pay more attention to smooth bokeh today. But there are certain looks you can only create with older lenses. Added to this they can be very cheap and you have a huge choice between thousands of lenses ranging from exotic ones with lots of “character” to some of the very best lenses available.
There are even 40-year-old primes with better image quality than many modern lenses. Of course progress has happened in recent years but still affordable primes are often sharper than very expensive modern zooms. Old lenses are usually beautifully built from nothing but metal and glass which makes it a joy to handle them. They can last a lot longer than modern lenses which are full of electronics and very complex designs, both of which make them more likely to fail.
They also hold their value much better than modern lenses. With some patience you can sell most manual lenses without a loss but with new lenses you can expect to lose 30% in the first year.
Manual focusing can actually be very enjoyable. This certainly depends on application but personally I enjoy working with fully manual lenses a lot more than with any AF lens and I would choose a good manual focus lens over an AF lens (almost) any time. You have to do everything yourself. You have to think about the aperture and set it manually. You have to focus manually. Some people don’t enjoy the process at all but I find this process aids the creativity.
So are manual lenses any good? For me the answer is “Yes, they are”.