I went from a Coralife PC to my NEP, I'm a newb but I can tell you myself, my corals and fish are all much happier.
There's even a fan quite mod available:
http://www.bderen.com/DIY/
I don't mind the fan noise as I don't find it annoying, but I may do it in the future if I've nothing better to do or a fan burns out.
I would like to go with a little more blue lighting when it comes time to change, and I certainly like the custom variations we can have.