I own both the Oktavas and the C-4's. The 012's are becoming as scarce as hen's teeth. I do believe they will be back, but I don't know when or who will be selling them. They make more mics than they can unload in Russia, and the U.S. market has embraced them.
That said, the Oktavas are darker, more colored, and less accurate than the C-4's. They are really good overheads. I choose them for rock/blues, or anything where color is OK. I choose the C-4's on jazz,country, pop, or anything where I want more transparency. They are great on miscellaneous hand percussion. On guitar, I like the Oktavas on cheap guitars with no balls. They sound great on an Ovation. I prefer the C-4's on really good guitars, Martin, Taylor, etc.
Basically, if the guitar sounds kind of thin, the Oktava adds bass and presence and fills out the sound. They can make a great acoustic sound "processed". The C-4's are more transparent, and will reveal the fact that you are recording a cheap guitar. If the guitar sounds great to begin with, the C-4's won't change that. That is why the Oktava can actually be used for a vocal mic with a pretty good singer. Don't try singing into a C-4, unless you're a diva or a sadomasochist.
Don't misunderstand me though. The C-4's, although I like them very much, are not in the league with Earthworks, Neumann, Schoeps, DPA, etc. I do believe that they are the best small diaphragm mics overall for less than $600 a pair. And I'm pissed off about Oktava, because they were the best SD mic under $100.-Richie
