I have not tried there Redux series of fans. But i have no complaints about my noctua nf-f12 ippc-3000 pwm fans, that i use 3 of as CPU cooler fans. Im very impressed by them. The only negative for some people i can think of with noctua fans, is that as far i know noctua still dosent offers fans with either LED or RGB light. Also i think its great that notua offers fans with other colours than those nasty ones on there old series of fans.
The Noctua Nf-f12 industrialppc-3000 pwm fans i have. Have a really wide RPM range. Remember these are 3000 RPM rated fans, they can still manage at 8 % PWM duty cycle only rotating 280 RPM and at 100 % PWM duty cycle just below the 3000 RPM mark. PWM duty cycle at 7 % they have a rattle noise because they are not rotaing and at PWM duty cycle 6 % and below they stop just as the redux fan in this test. Noctua Nf-f12 industrialppc-3000 pwm is for me the perfect fan, because it has no annoying RGB light and a very wide RPM range so they can be dead silent at low load and move some serious amount of air at full power (with the penelty of noise, cause yeah 3000 RPM fans are nt silent at full power) + they have a high static pressure rate perfect for air or water cooling use. When the fans first are spinning i do not here any motor noise what ever its at 300 RPM er 3000 RPM. Noctua PPC fans has really impressed me as well and its not the last time i buying noctua fans. Only bad thing about there PPC fans is that they are not cheap.