A central sump system may be the easiest to clean, but is the biggest electricity user because it has to lift several feet of head and overcome many feet of pipe friction.
Canister system is easy to set up, but tedious to clean. It uses less electricity than a sump system, but not a whole lot saving because it still has to overcome long pipe friction. Canister just hide waste out of sight, not a healthy system if you use it to procrastinate cleaning.
Like eveyone said, a central air sponge system is the most energy efficient, and easiest to set up. But the system does not provide any mechanical filtration, so you have to do frequent WC to remove visible wastes. An air sponge system can be the most healthy system because it doesnt allow you to procrastinate cleaning.
The middle ground is HOBs. HOBs are low energy user by design because they only need to lift an inch of head and don't have long pipe friction to overcome. HOB motors are rated only 5 to 15 watts maximum. HOBs are excellent mechanical filter but require frequent filter changes, more so than sump and cansiter systems. But changing HOB filters is quick and easy, and frequent changing provides cleaner water, healthier environment and less WC need.
