I have had several Fluval canisters that were a pain, but I'd recommend this brand to anyone.
Fluval could be the reason I am anti-canister. It could also be that it's because I change my filter media while doing water changes. It convenient to do them while I'm babysitting the hose either filling or draining tanks.
IME, I can't remove the top of the unit without at least a little water spilling, so I have to do all maintenance over a tub. There's also a lot of nasty water at the bottom, so I have to remove all media from the unit every time. Then despite topping the canister off, once I reconnect the hoses 1/2 the time it'll prime nicely and 1/2 the time it won't. However, 100% of the time I have to rotate it about the vertical axis to help the bubbles work themselves out if I want it to be perfectly silent.

... vs HOB Emp 400s - I flip a switch on a power bar, they all turn off, drain the media containers, replace filter floss in said containers, drop them in, and flip the switch back on for all filters once the tanks are refilled.
