+1 to kellsindell. I've heard mixed reviews about the Coralife, but more negative than not. I never used a Coralife, but I'm still pretty positive that there are much better ones out there.
On the other hand, I;m pretty sure the Aqua-C skimmers are awesome. As a matter of fact, my next purchase for my saltwater tank is going to be an Aqua-C EV-180. I currently use an Octopus NW-150, and while it has served its purpose over the past year, it has still left me wanting more. Plus, I have to periodically clean out the air intake tube of saltcreep to keep a good flow of air going. The Octopus is a venturi system of drawing in air with a needle wheel to chop it up into fine bubbles, which I believe is the same as the Coralife. The Aqua-C uses a completely different method of air injection and bubble creation.
If you're wondering which to get between the Coralife and the Aqua-C, then go for the Aqua-C!