The U87 is a classic mic, probably one of the best they still make. I would buy a used one as long as the capsule was in decent shape as the newest ones are not quite as good as certainly not worth the extra $1,000. Its hard to go wrong with a good U87 but they are not the best Neumann ever made and they don't work on all voices or sound sources.
If you had unlimited funds and a tolerance for dealing with old electronics, the VF14 equipped U47 is the king. Tube M49's and omni M50's are great. U67 mics (with the EF86 tube) and M269 mics (with the AC-701 tube) are amazing. A lot of tube U47's and M49's have been heavily modified by BLUE and other people so a U47 from someone like that might only be 10-20% real U47 and the rest made up of all kinds of non-Neumann stuff. This may or may not sound great and I would be careful about these. The very rare U77 mic is amazing (I have one), and does not sound like a U87, but these are very hard to find.
There are many great small diaphram Neumanns as well like the KM54, KM53, KM66, KM74, KM73, KM76, KM83, KM84, KM88, just to mention a few. These are used mostly to record instruments.
Also worth mentioning are the U89 and the TLM-170.
Neumann was sold to Sennheiser in the early 90's I think (not sure) and the newer Neumanns are not as well respected as the vintage models, but that is not to say they are not good. The main difference between the old ones and the new ones are the way the circuit boards are made. The new ones use automated machines and surface mount components. Its cheaper to make a mic that way, but the older hand made ones with discrete components hand soldered are the ones that are most respected.
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