If noise is of no concern to you, then those are great. Otherwise, forget it, because those will drive you out of the room in a matter of minutes. I just replaced my NF-A14 PWM 2000rpm rear exhaust fan with a normal NF-A14 PWM chromax.black.swap fan because I just couldn't handle the irritation at the sound and harmonics of that fan compared to the rest of them, even at low loads, and I had plenty of thermal headroom anyhow so it made really no difference overall.
But, all of the Noctua fans are very good quality. So are Thermalright. (Not to be confused with Thermaltake, which are generally not that great). Both these companies have very good quality, very quiet fans.
Really, it matters WHAT and WHERE they are going to be used for. Just slapping a fan with a very high RPM, CFM and static pressure rating, on, may not make sense in a lot of situations.