As it turns out, I own a pair of C-4's, a pair of MC012's, and a pair of KM184's.
The C-4's are brighter, more accurate, and less colored than the Oktavas. The Oktavas rock as rock or blues overheads, where I would choose them over the C-4's. I prefer the C-4's on jazz and country, where I want a crisper sound. I prefer the C-4's on acoustic guitar or as an orchestral/choir stereo pair, but the Oktava can actually be used as a vocal mic, with 2 pop filters. Singing into a C-4 is not pretty.
The Neumanns are in a different animal altogether. They are simply superior to either of the above, on pretty much anything except vocals, where the Oktava's dark nature and color can actually work. The high end detail of the Neumanns is simply a whole step up from any inexpensive mic. Many engineers think the KM184's are too bright, but it's easier to take away what's there with EQ, than to try and put something there that wasn't there in the first place.
Other engineers will prefer the combination of color and detail of the Josephson C42's, and others will say the Shure SM81 or AKG C451 is a better buy. Trust me, I like all of those mics for what they are. I frankly prefer the Neumanns to any of them, except the jury's out on the Josephson's, because I've had very limited experience with them, like 5 minutes. I've also had a limited opportunity to play with Schoeps CM6 and a pair of DPA's, which *ROCK*, and ought to, at those prices. I've never gotten to use the older KM84's, but a majority of engineers seem to prefer them to their successors, the KM184. There seems to be a minority that disagree.
In short, the Oktavas are a *great* pair of mics for $100 (what I paid for my pair). The C-4's are a *great* pair of mics for $320, and the KM184's blow them both out of the water, which for $1500 a pair, they should. Whatever the super AE's say about the KM184's, they have certainly been a pure joy to work with in the studio. I did a series of retro-recordings of
a rockabilly band using the Neumanns as a stereo pair into an Avalon AD2022, and the detail is amazing. They picked up the whole band, every cowbell, lead, bass, vox, and you can hear the drummer breathing. That is what I paid the price of admission to hear.-Richie