I've searched through various forums and generally the consensus is to favor a certain brand over the other.
I currently have a Penguin 170 and mini, Whisper 20 and Aquaclear 300 HOB
filter and they all have been working fine for years.
Below is just my experience based of no scientific testing.
I like the Penguin because of the Bio-wheel, but the filter media is more expensive than the Whisper and has less surface area for mechanical filtration. When the filter begins to clog, the water level rises in the chamber and begins to overflow back into the tank without going through the media.
I generally change out the media once every 2 or 3 weeks on all my filters and the Whisper has never clogged the way the Penguin has. Maybe that's a plus for the Penguin since it's trapping detritus? The Whisper will lose significant flow, but it will continue to filter unlike the Penguin.
I like the Whisper because it seems to be the best at mechanical filtration and replacement media is cheap; approx. $1 per cartridge. I dislike the Whisper because it does not have a bio-wheel type stage for bio-filtration. Although there is an additional foam filter after the cotton/carbon media which I assume is to serve the same purpose as a bio-wheel. I usually rinse it in old tank water when I replace the cotton/carbon media.
I like the Aquaclear is because it holds the largest volume of media. Since the foam is suppose to be on the very bottom stage, I dont feel like it does well in mechnical filtration. Instead of replacing the foam everytime, I generally just rinse it in old tank water and it isn't as dirty compared to the Penguin and Whisper filters.
A benefit of the Aquaclear is that you can fill it with tons of bio-max or similar media which does wonders for bio-filtration.
, this is how I see it...
Aquaclear for max bio/chem-filtration.
Whisper for max mechanical filtration.
Penguin for medium bio/chemical and mechical filtration. A compromise...
On quality, the Whisper has been the quietest of the three brands. The Penguin 170 is making an annoying noise form the impeller area. Probably needs a new impeller. The mini has been silent.
The Aquaclear sometimes makes a buzzing noise coming from the lid caused by the resonance from the motor. I've also come home a couple times to find that the impeller stopped spinning for no apparent reason. A couple taps and it starts right back up.
Please feel free to comment or share your experiences with any HOB filter.