So they're practically the same..........The 2nd inline diffuser that you listed has an air stone to break up the bubbles which then mixes with the water and goes into the tank.
the atomizer has a air stone in the middle that chops up the bubbles even more which allows even more effective mixing.
Where did you get it from....link ?!?!?Well went ahead and bought one of the atomizers. Got it for 23.99 free shipping and its a seller in New York, not China. Pretty excited to get that bulky power head out of my tank.