Fractal Define R4 vs Thermaltake Chaser MK-I

I really like both of these cases - Fractal Define R4 and Thermaltake Chaser MK-I. Right now newegg has a deal and rebate so the MK-I is only $100. And the R4 is $110. I am not sure which case to get. I really do want a quiet PC, so I am wondering how much quieter is the R4 compared to the MK-I? Is the difference going to be substance? Is there a way I could make the MK-I just as quiet? And which do you prefer?

Thanks.