Also how loud is the noctua nf-a14 flx using the ULN adapter compared to the nf-a14 uln version of the fan. With the adapter it's still 100rpm faster than the nf-a14 uln but it would be nice to have the option to crank the fan up a bit on really hot days. I'm just worried even using the lowest speed adapter it'll be too noisy during silent nights but if these fans are as quiet as some say maybe....
SPCR released a roundup recently with the NF-A14 FLX/ULN, in case you want to check it out, First 140 mm Fan Roundup: Noctua, Phanteks, Xigmatek
I have heard good thing about the BeQuiet 140s, but never really tried them =(
I have R4 on my way atm for haswell build, so take my comments with a grain of salt as i haven't tried anything yet, but my plan is to move the included back fan to the front and test them to see how they are, and just to buy a Thermalright TY-147
and place it as case fan on the back of the R4, kinda matching the airflow with the included fan on the Thermalright HR02 Macho
(still debating on trying Silver Arrow). If the Fractals 140s are not that good, ill go for noiseblockers,Noiseblocker NB-BlackSilentPro PK-1 140mm x 25mm Ultra Quiet Fan - 700 RPM - 9 dBA
( i own two and they are great imo)Noiseblocker NB-BlackSilentPro PK-2 140mm x 25mm Ultra Quiet Fan - 1200 RPM - 20 dBA
(this i kinda want to try out of PK1 having a limited dymanically tweaking the voltage, check the bottom review).Cooling Technique Review Noiseblocker BlackSielentPro PK series