Recently, I tested M 147 against U87 Ai, and ended up buying the latter... To my ears, the M 147 was too bright on sybilants, and considering the fact that I mostly record people singing in Polish (LOTS of ssssssssssss), I went for U87 Ai.
However, Neumann themselves suggest M 149 as your first choice for lead vocals and background harmonies (U87 being second). So if I had the money, I would like to test M 149, too.
Back in the day when I lusted after an M149, but would have had to pay $4 grand for it, I took a chance and ordered a Lawson L47MP for half that price. Never regretted it. You have to order them direct, not in stores, but you can keep it for a week and return it no questions asked. These days the price differential isn't as great, but since you were considering the M147, you could also consider the cardiod only version of the Lawson for even bigger savings - probably around the price of an M147.
I too have not heard great things about the M147 - some say you might be as well off with that StudioProjects tube mic, or the Rode tube, although I'm guessing the Neumann is probably a little less noisy.