The Euroreef has three lines of skimmers: RS, CS and RC (in ascending price).
To my understanding, they are all the same basic needle-wheel design of which ASM (and others) are clones of.
The difference is construction and pumps and recirculation options.
The RS series is made of cheaper plastic and has cheaper construction (I think exactly the same as the ASMs) than the CS series. Essentially, the RS series is a clone of the ASM cloning of the CS series!
The RC series is built like the CS series and adds re-circulation.
The smaller Euroreef skimmers (all lines) and all ASMs use Sedra pumps. The bigger Euroreefs use Gen-X pumps (supposedly more powerful than Sedras) and will reportedly have Eheim pumps available soon (definitely better than Sedras).
http://www.euro-reef.com/products-sk...techspec.shtml