It depends on what you want.... Silence, air flow, or a balance of both. Another factor is the TYPE of noise. Some people prefer one brand over another because the frequency of noise is not as annoying.
For instance, I replaced some expensive Scythe fans with cheap Yate Loons. They were not a big drop in decibels but the frequency of the noise is much lower and doesn't bother me at all.
If you just want a max airflow 120mm fan, nothing beats the Scythe Ultra Kaze, but it's thicker than a standard 120mm fan and loud.http://www.newegg.com/Product/Product.aspx?Item=N82E16835185054&Tpk=scythe%20120mm%20fan