The RCA 77 is a classic ribbon microphone known as one of the best ribbon mics ever made. It is made for use in the studio, and I wouldn't recommend using this mic, or any other ribbon mic outside of the studio in a live setting. The microphone is built well even though they are old and should stand up well over time, as many of these have. RCA was the original manufacturer of high end ribbon microphones and this mic holds its own special place in recording and audio history.
I've been using the RCA 77 ribbon microphone for about five years. This mic has a reputation for being one of the top ribbon mics of all time and I am never ceased to be amazed when I use this mic. It works great in a number of different situations, including for vocals and drums. It has an extremely warm sound that cannot be matched with anything other than a ribbon mic. The look of this microphone has taken on a life of its own, as its look is mimicked on talk shows and pretty much all over the place. While like all ribbon mics, the RCA 77 is somewhat fragile, if you treat it right they are known to last a while and there are quite a few of these around that have been around for a long time. If you can get a vintage one of these used it will cost you a bit but not as much as you might think. This being said, I wouldn't expect to see one of these in a home studio as these are pretty professional microphones and are aimed at high end recording. Compared to the RCA DX77, I probably like it better than this mic, but that is just personal preference. If you are looking for a classic ribbon microphone the RCA 77 won't let you down.