Both are great filters. The Eheims are VERY quiet which is why I have 2 of them on my 90 gal tank in the living room. The Aquaclears are not quiet to the point that they can be somewhat annoying at times. If the tank is in an area where the Aquaclear sound will not make a difference (fish room, basement) then they are a great option. If the tank is somewhere you would like a quiet filter (TV or music room) the Aquaclear may be bothersome.