bubbles popping splash roots above the water line. this is what makes the roots grow out of the net pot and hang, eventually hanging into the water. this is a very important aspect to dwc.
better is a matter of opinion and lack of experience with other products/techniques. i use a commercial pump with 12 outlets. hung from a bungee cord, it's not audible from ten feet away and not intrusively loud when you are standing in front of it. my fan is 100 times louder than the air pump.
i also keep mine at the ac register, so the pump is always cold, never gets hot (and therefore pumps cold air into the buckets).
i've had the pump for almost 12 years and it still operates like brand new. i use it to power up to 12 10.5'' commercial airstones, which make the water 'boil', but with no heat. placing the pump at the ac register makes the air pump a water chiller as well. dual purpose, effective, efficient, and cheap (when compared to three of the gh pumps for half the job, a chiller and external res, extra plumbing, etc)...