If you get a new one, don't get the h110. The h110 is old now. They have a newer model thats hardly more money but its a better performer, called the H110i GT. It uses 140mm fans so you'd need that to fit of course.
This article should help answer your question.
http://www.guru3d.com/articles_pages/corsair_h110i_gt_review,11.html
Be aware though that the 4790k uses a lot less power and makes a lot less heat than the 5960x. You can see by comparing the Baseline to the Overclocked result that the water cooled solutions start to pull away as you increase thermal load. Extrapolating, the H110i GT should pull yet further ahead on a 5960x. Note this improved performance is at exactly the same sound level as the d15 as well.
If you're going to spend $1000 on a CPU I dont think it's much of a burden to get the best AIO water cooler for it. Those 5960x's are supposedly pretty dependent on good cooling to get a good overclock (so that you don't lose much frequency for going up to 8 cores). I put one of these with an additional 2 fans push-pull style on a friends 5820k and the temperatures were incredibly good. I'm not sure how much more you get by adding 2 more fans though.
All in all the d15 is still a very competent competitor and it would work great if you aren't overclocking, and would work for a moderate overclock as well.