Very impressed the the R4. I just got it and put it together. Between my fortress FT-02 and TJ08-E, this case is dead silent. I did replace the fan however though. I got all the new corsair 140mm fans for intake, three 120mm fans for side vent, 212evo cpu cooler, and exhaust. I also had to flip my psu upside down to intake air from the case since the case rests on carpet and wasn't getting air. I can attest that even with the stock fans it was pretty silent. Also newegg was running a deal, you can probably still find one for the blackout edition for $79.
I have to say I'm really impressed with this case.