I have 3 of them. I bought them at different times. I really like them and they will run for years as good as a new one. I don't think they clog any more than another canister filter. I've even used them for young goldfish (and goldfish are messy!).
I use them with out any carbon.
The set up is kinda backwards (as the bio media is infront of the sponge) however it does not seem to make a difference really.
Hope this helps. What will you use the filter for?
Mines is working fine without any problems. Just keep it clean as any other filter and no issues will occur with clogging. There are tons of reviews out there and I'm sure you can get a general consensus of this filter.
Love them! I've got four in use. So long as you keep them clean, there are no issues with them clogging, but they do have to be cleaned, and the larger the bioload the more often they need cleaned, just like any other canister filter. In a couple years of use, I've lost one impellar because the tank level got low enough it could get water and overheated.
Very durable - I've accidentally left it gulping air for at least a day and no perceivable damage. Hardy filters that are very simple but very effective.
All I dislike (which isn't something you can really avoid to be honest) is maintaining the pipes in certain positions. The pipes are large enough and the filter is light enough for it to be knocked over sometimes.
I loved mine on my 5.5. I now have a 6 or 7 gallon (can't remember and haven't cared to figure it out) and even that little difference has seemed reduce the flow in the tank quite a bit. However, it has been vary reliable for about 4-5 years. Super quiet as well. I don't know if I would buy one again, I would look into Finnex or a 511 instead.