I've looked at the AquaClear, so far had the MarineLand (Pengiun 1140 & Maxi), the Cobalt, and most recently, the ZooMed - I like the rotational function of the ZooMed, but the diverter flap kept falling off, and the flap on the Cobalt was WAY too loose and would just flatten out (& the Maxi is HUGE!)
I got the ZooMed because the cust svc person I spoke with said that the airline DID go *on* the nozzle like a bubbler - it doesn't.
I like the combination functions of aeration, flow, and sponge filtration. Those functions from all of them were just fine, it's just the fact that the blasted airline slips out of the hole SO easily. It's no big deal if you have small fish like dannios, tetras, or neons. But I have active cichlids, a 13" Black Spotted Eel, and an 18" Brown Spotted Highfin Pleco (one swipe of the pleco's tail is practically enough to re-arrange the blasted tank, lol)
Ticks me off that it would be SO easy for any of them to change the design (or to have designed it "sensibly" in the first place). Even if they came out with an adapter for it (or if I could find something that would work as an adapter - since all the holes are the same size, and about the same depth).
I found all of them to be equitable otherwise (with the Pengiun being the lowest maintenance/easiest to clean - but the worst with respect to suction cup life) - I'd even pay extra for magnetic mountings. Blasted suction cups have SUCH a short lifespan