I'm just testing the new revision of that Noctua cooler with the 140mm fan and to be honest, it's not on par with proper tower heatsinks.
The only reason to get a top-down cooler is if you are limited for space, in which case the Noctua is winner.
If you don't have space limitations, the new Noctua NH-D14 for about £10 more is way better than the top down cooler, by about 15 degrees!