Well I have had mine for almost a year now, and I am completely satisfied with this skimmer. For my size tank it is a workaholic. IMHO I would not recommend it for over a 55 gallon tank. But for smaller tanks it is a great little skimmer, once "tweaked", as above posts have advised.
Now mine runs constantly with the adjuster set to 2 o'clock (looking from the front of the tank). In the beginning it was barely open, but once it settled in this is where it leveled out. BTW, don't expect this skimmer to work at all if your tank is new, it may tank several weeks to a couple of months. Won't work at all if your tank is too clean.
HTH
Hermit