i've used the emperors, and penguins filters (i've never tried the topfin though), and am not very impressed with them. i think i'm stuck on aqua clears. i've become a big fan of these. i currently have two ac110s, two ac70s, and an ac20. the ac20 sat in my brothers basement for several years, then he gave it to me where it sat in my basement for several more years before i finally fired it up, and it still runs like brand new.