I've never heard a BK but my ATB is pretty **** silent with the askoll motor. No pump noise, no air noise. I'm not saying they are quieter/better than BK's but I know mine is very quiet. I do like the adjustable pump BK's but I read too much about how much it costs to get a replacement pump and time it takes, having ATB in simi valley was the clincher for me. Dealing with Chad is great