Noctua is overpriced. 212 EVO is the sweet spot right now on coolers.http://www.hardwaresecrets.com/article/Cooler-Master-Hyper-212-EVO-CPU-Cooler-Review/1407/6
D14 can be found at 39c delta, the 212 evo is at 36. Not sure what the extra $50 gets you but more broke than before. In thier 212 + article, its 44C, the EVO improved cooling quite a bit.
The C14 is oriented different and helps cool the motherboard around the socket itself, why you see it performing better than the D14.