I've used the magnum 350 on my last two tanks. A 75 gallon, and now I have two on my 150 with a FX5. These are some pretty decent filters, not the best, but they do get the job done. They are lacking in the area of holding alot of bio media, BUT, as a compliment to another filter, they are not that bad. I like running multiple filters, as you can rotate their maintenance schedule and not have to open them up every month to clean them. I let mine run about two months to three months before they need cleaning. Also, if you are needing to polish your water for that CRYSTAL clear look, they do a nice job on that. If you are on a budget, and want to run multiple filters, IMO this is not a bad filter at all. With the quick disconnect valves, it makes it alot easier during maintenance.
My stock levels on my 150 are two Oscars 12" +, a common pleco, 8" GT, and soon as my Festae get big enough, they will go in also.