I bought this to replace an extremely unreliable skimmer from a now-defunct brand, and was tempted by a sale price. Good points: relatively small footprint, easy setup, DC motor, quite large collection cup, nice controller, and the dual pump sounds good in principle. However, all that is overshadowed by performance problems. It is set up correctly, and I've played with water height and other factors a fair bit trying to improve things. It seems to pull relatively little air as compared to my other skimmers. I suspect (and I'm guessing here but it seems logical) that the two small pumps just don't pull enough water each to in turn suck enough air in there. As a result, performance is just OK. Second, and more serious, its inconsistent. In the first month of use, it went "nuts" and started overflowing water into and over the collection cup five times. No clue why, I carefully inspected it each time and there were no clogs or other visible issues. For some reason it just stopped pulling air for the most part, leading to too much water flow.
In the end I'm sorry to say I'm regretting the purchase. I have four skimmers in various tanks and the other three, while more expensive, have performed perfectly needing only routine cleaning to keep going. Should have gone for what I know.