Sponge filters are defiantly my go too with 17 tanks in the Fish Room. Although I do use a little of everything. I also have 6 HOB’s and 2 canisters. I love the sponges because they are so easy, and they all run off 3 large air pumps. Larger tanks, or larger bio loads have 2 sponges. When I’m wanting to start a new tank, I just grab one out of a tank with two and replace it with a new sponge. Now I can have a new aquarium with a pre-cycled filter, ready to handle some fish. I have to say my least favorite filter is the AquaClear HOB’s, I can never keep them running properly for long. I have thrown all of those rattling lids away, before I removed the sponge out of them they were constantly pushing everything out the top. Even had one overflow onto the floor. Now I just use them with bio-bags in them, no sponge material, defiantly less headache since then. I have 3 different sizes, all the same junk, never again. I guess my second favorite would be Marine Land HOB’s, I have 2 big ones, not sure what size on the back of my 125g. They have been running strong now for 25 years, replaced the impellers twice, that’s it.