I believe the person meant, she got 1 of the Emperor 400 filter (the one with double - 2). I think people are misunderstanding that she has 2 of the Emperor 400 filter.
I have 1 Emperor 280 filter and the only flaw to the filter, the intake tube is too wide. Its not a problem, so you just have to put a plant in front of it (with enough space between the intake and plant). Another thing about the Emperor, it produces more bubbling waterfall than the Penguin filter. Its a good filter that produces extremely wavy water.
I also use the UGF with the traditional method and I am happy with it. One thing about the air stones, keep the air going as long you can. Once the air pump stops (by unplugging), the air stones will (i dunno what it does) lessen the bubbles amount (air flow). When I got a brand new hood, I had to unhook the air tubes from the 3-way to insert thru the holes in the hood and connect to the 3-way again. Sadly, the air stones suffered, so I have to get new air stones to maximize the flow again.
Thunder