I would definitely have to agree that the Deltec mce-600 is the best HOB currently available. Unfortunately the Deltec is very expensive, as melonbob pointed out. The remora can be problematic as each one is hand built and the injector can vary in height. The remora also is dated in its technology as it uses a injector over a pinwheel or needlewheel design. The Corallife SS can have overflow problems and can dump microbubbles into the tank. But is a good skimmer for the money and is popular because it uses a needlewheel design, which is efficient and can produce good skimmate. The best solution for skimming is easily in-sump skimmers, they will produce much more skimmate for the same price as HOB skimmers. The Octopus skimmer has an 8" body and is about 24" in height, it runs about $175-$200. So when you compare it against HOB skimmers in the same price range they don't compare. The octopus skimmer would probably run in the same league as the Deltec, which is 3x the price.