We have a rather large number of "Crap" fluval 404/405's running with no problems at all and, in fact, have others on order. The seals work just fine as long as you follow the directions (lubricate and peroidicly replace them)
The flow rate when loaded is almost 3 times that of an xp3. (measured with an inline flow meter.) The xp3 in question was then moved to a relitives aquarium for the 4 months until it's case split and we trashed it.