Current Eclipse filter vs HOB penguin (or any other HOB)

As some of you may know, i have a 12 gal eclipse tank and im currently upgrading the lighting to a 150w metal halide. And alot of people said to change the filter to a HOB penguin or something comprable to that. So i looked and it seems as if these are almost the exact same filter that came with the tank. The filter that the tank came with is the filtration "Pad" w, filter carbon, which flows into the biowheel. This appears to be the exact same situation than the HOB systems...so why would i but a HOB when i have the exact same filtration (just a different style)? I know the tank isnt meant for saltwater but so far everything is doing great (i want to get some sweet corals now, thats why i bought the metal halide. Currently i dont have any corals just some live rock (approximately 14 lbs), 1 jewel damsel, 2 clownfish, 2 porcelain crabs, 1 eel cleaner shrimp, 4 blue legs, and 1 carpet anemone)

thnx

Brad