Just going from reviews and from what I hear on Toms the Noctua is supposed to the best that is one of the most highly rated with that said I dont think you can go wrong with either one try a search on toms on Noctua NH-D14 and you wil see many recomendations of that cooler
BUT, the Heatpipes on the second link is way better than Noctua Heatpipes... Is there any test or reviews on both link together?
this article compares 9 different coolers
from reading it the Noctual is rather large and hard to fit though it is the best air cooler so the Zalman would be the easier fit
Check out this site... the Noctua is your best bet:
Agree everywhere you read on the web teh Noctua is considered the best in its price range only complaint if size and fitting it I dont think you would want to use it on a mATX board definitely would have trouble with tall ram like Ripjaws
The Noctua is better in terms of cooling but the Zalman unit is no slouch either. I do believe the Noctua unit is the quieter among the two. So obviously, it comes out the winner here. Now what are you going to cool with it? And are you sure it fits your case? Its a huge cooler.