Oktava's quality control is attrocious. *If* you get a properly matched pair, they're great neutral all-purpose mics, until they stop working. Apparently the Sound Room claims the QC has improved, we'll find out in 3 years or so. I wouldn't trust eBay sellers to have new "better QC" mics, since the old stock was dumped really cheaply, $49/ea at Guitar Center for example. You'll pay about 10x that for a reliably matched pair.
I recommend anyone considering MC012's to check out Rode NT5's or an NT4, which I think are better suited for dealing with the shortcomings of compression horns. There's eBay sellers unloading those cheaply too, and they're 100% reliable for a factory match and solid build. My NT4 once took a nose-dive when a stand was knocked over, 8' drop capsule-first onto hardwood - not even a mark, and they still match.