ac110 all the way. I have used both on many occasions. And i personaly like the ac's way better for one they come with sponges that last a long time just rinse and reuse. They have carbon and bio max. I take out the carbon and dont use it. Put in another bio max bag in it instead. And put the carbon in only when i use meds on the tank to get rid of them after there not needed any more. I have allso use these on salt water set ups with nothing in them but sponges and work well that way to. In my personal exspereince the ac's last longer then emperors. The emperors perpellers die quicker. I actually have a emperor now that i have to put a chope stick in the perpeller and push it around to start it after i shut it off. The only problem i have ever had with the ac's is if you use small particular sand it clogs the hell out of them. But if you are not using small particaul sand they are my all time favorite hob filters. Allso as stated above they are super quiet. They allso have a adjustable flow rate. Which is allways a good plus