I am happy with an Octopus on my 270. Smaller versions would work better for that sized tank. I upgraded from a Vertex, which was also good, better for the price, but undersized for my tank. I used a lot of skimmers before these two and wasn't happy with any.
I would go needle wheel or similar on that sized tank. Lifereef or similar designs might be cheaper and easier to operate on a much bigger tank, but all are too big for a 75.