Im currently using two Huey Hung HH-03 sponge filters in my 4'x20"x15", i was unsure i was making a good choice when i bought them, given the ultra low price of £10 each delivered.
They are doing great so far in my opinion, and with regular substrate vacuuming my water is crystal clear to date. The HH-03's seem to catch quite a bit of debris when the substrate is kicked up, or at least in this tank, with an over-powered air pump they do.
They also have clear outlet tubes, so should be easier than some brands to hide when the tank is planted and fully decorated.
Also i suspect i may be able to run a heater in-line with one of these and a small powerhead to distribute the heat better, as seen in some canister setup's. I guees i'll have to see when my 'rena smart' heater is ordered.
Nice article!