Depends on usage, case, airflow, gpu. There is no 'best' as such, if you sli then blower definitely, if a small or mITX case, then blower, if pushing hard 4k limits then an overpowered gpu like an FTW 3 and limit the boost. The twin-frozr fans on msi work extremely well, the triple fans on Giga cards do just as well.
The top-line cards have better cooling than the lower tier cards, so an msi gaming x will do better than the Armour 2, unless you push the boosts, then they are equitable for temps.