Not counting sonic differences (which among fairly flat small-diaphragm condensers can be very hard to quantify) the Oktava's can be had with omni, cardioid, hypercardioid, or large diaphragm cardioid heads. The NT5's are cardioid only.
I have an Oktava from the Sound Room with the cardioid and hypercardioid capsules. My cardioid sounds very open, airy and detailed but without sounding overly bright or harsh.
My NT5 pair sounds more sterile, and seem to have a tighter pickup pattern.
I generally prefer my AT3031's over the NT5's. Mine are a little quieter and sound more open, but still have a tighter pattern than the Oktava cardioid.
None of them would be my primary choice for VO. They don't give the pleasant warmth of a larger diaphragm mic that's intended for that type of work.

I see... so I guess it's the Oktavas then...

So how about a pair of AT3031's? (from B&H)... These seem to be cheaper than the Oktavas but are cardoid too.... better than NT5's tho huh?

Dennis

Hmmmmm... what Jay said. ;-)

Seriously, my experiences comparing the MC012's (Sound Room) and the NT5's are in the same vein as Jay's comments.

The reason none of us recommend SDC's for VO is because they rarely flatter a voice - sterility comes to mind. Though I said that they are an option for VO earlier, my own personal experience is that on most voices, LDC's do flatter more, thus they sound better to most people's ears. As I posted in an earlier thread about mics for VO, I've never settled on an SDC for final VO takes (meaning, on occasion, I try them, ALWAYS end up with an LDC), but I have spoken to a few people who have and like the results. It's like Scot says, it's just easier to reach for a mic that you know can do the job instead of burning precious time finding the "perfect" mic (of course, there are engineers that do that, and may they have much more time/budget/intelligence than I). In the end, try, try, TRY to get your hands on a few different mics and do some test runs with whoever will be predominately doing your VO work. Check out the earlier thread on Microphones for VO for the rhyme and reason about the VO side of things. Variance in voice is far more dramatic than the variance between a MC012 and NT5. Your chain starts with the talent as being the first link.

Scot's question about the MC012 on a boom reminded me of a poster a few months back who was putting together a low-low-no-budget audio rig using a MC012 on a homemade boom (light pole from Home Depot) with a DIY fuzzy windshield to be hooked up to his laptop in his backpack. Never heard what came of that...