I have ordered from them and would not again. Their guaranty policy fails to state that your store credit can't be used on sale items. The owner, Scott, takes the position that he can limit the use of a store credit when he puts product on sale, which is really quite often (roughly every week). This "arbitrary" limitation is no where to be found in their website, and Scott claims that he can't change the language on his site. As far as the quality of the corals, I would simply say that they certainly don't look as great as the photos, but they could not be described as bad.
Bottom line, buyer beware. Extreme Corals has an extremely poor guaranty/store credit policy!