I would not call them better than the other....
I have used 5 different compounds that include the Tuniq TX-2, Zalman STG1, Noctua, OCZ and AS-5... All 5 run @ the same temps under idle or load (some differ from other's by -1 or -2c at the most)..... So in all its a matter of taste... Don't think that you will drastically lower your temps just cause you went from AS-5 to the Tuniq paste....It does not work that way... The cooler is a major factor when comparing different compounds...