indigo
Fish Fanatic
im running 2x 404's and i've had a few teething problems with both, ie breaking the propellers which is an easy thing to do, but apart from changing all the pipes, fittings and O rings i've had no problems with either, i only changed so much on there as they're 4/5 years old and came with the tank that i inherited from a family member 
i'd replace with another fluval for sure in the event of them being beyond economical repair in the future
give Hagan a ring, when i rang them almost in tears that i was having problems with one of the filters when i first got them, and explained that the insurance had arranged for a guy to install the tank but that he hadn't explained fully what he was doing and when i checked a filter over a few weeks later i managed to break the propeller, they sent me a shedload of spares, gave loads of good advice on the phone and have been very helpful ever since
i'd replace with another fluval for sure in the event of them being beyond economical repair in the future
give Hagan a ring, when i rang them almost in tears that i was having problems with one of the filters when i first got them, and explained that the insurance had arranged for a guy to install the tank but that he hadn't explained fully what he was doing and when i checked a filter over a few weeks later i managed to break the propeller, they sent me a shedload of spares, gave loads of good advice on the phone and have been very helpful ever since