i have both. i believe the fluval to be a better plug and play setup, you can get it going in 10 minutes. the magnums take a bit longer, but are just as good if not better. i use them on my tanks a few times a month for carbon filtration, but i'm sure i'll get flamed again and again. some people think cannisters are useless and unnecessary. if you do decide to use one, plan on cleaning it about as often as your skimmer. i wouldn't run a carbon bag more than a day also. throw some bioballs and/or lr fragments in a section of it.