The fancy coolers improve your cards cooling so you don't have a hoover running under your desk 24/7 while playing.
They also can cause rattling fans (in the case of my friends 7870 from sapphire which had rattling fans and stopped working one day and had to be RMAed but was damaged in shipping and thats his fault now i guess)
And they also can be made with terrible parts (in the case of someone I knew on a minecraft server in which his MSI twin frozzer 760 which had a capacitor blow up, so much for "military class caps")
And my galaxy 560ti that would get up to 100*C (or atleast thats what the temperature program maxed out at) and had fans running 4000 RPM constantly but galaxy said it was my fault because it was running on "bad power supply" (seasonic 850w is bad now i guess). Finally when that card gave out I pulled it apart and did a delid on it. Turns out the TIM between the actual GPU die itself and the IHS was not even installed. (not talking about heatsink TIM and GPU IHS here)
Example of what a delid is(on a i5 4670k):
So far my old "Junk" reference 660ti from EVGA has been working fine for a year solid now. (which btw the fan never goes over 2000 RPM in any game and temps never over 70*C)
The only company I have not heard bad about is ASUS and EVGA so im with them.