Northsiderap notes there have been recent threads on this, and I expect I would have already commented in one of them.
However, I might as well do so again. An acquaintance of mine got a pair, returing them because he was dissatisfied.
I was not convinced of the reasons for his dissatisfaction, so I bought a pair as a challenge (um, mainly to prove him wrong). Because they were so cheap I had little to lose: a pair of mikes for the price of two tanks of petrol!
I tried out a few things with them. I didn't find them noisy, but they did seem to be less sensitive than, say, the NT5s I have. If I turned them up to compensate, then the noise I got was not from them, but more from elsewhere in my system.
I have recorded things using the c2 and something else, then asked for preferences. Some say one, some say the other.
I have recorded vocals using it (something I would not normally do with this style of mike), and they came out ok.
For the price, they are hard to beat.