I can't say anything for the Octopus, but I had an NAC6 for many years. On my 50g, then onto my 75g with 11 fish at one point. It ran like a champ and produced some nasty nog.
Only issue with it, as I think it's the same with any skimmer, is that I would have to leave it off for about 15 mins after swapping out my sock filter.
Other than that, flawless performance.