I read all the reviews and looked at the problems others were having by reading the user reviews at Newegg and Amazon. I'm sure that most heat sink manufacturers must have their own forums where problems are discussed.
I choose the Noctua because of their mounting system, foremost, and the NH-U14S specifically because it does not interfere with RAM slots. Cheaper assemblies typically have flimsy mounting systems. The Noctua fan mounting system is superior over many others, too. The Noctua cooling fans are the best in the industry and also the most quiet. (I bought a $50 case and spend over $80 on just case fans.)