Just to offer some input, oftentimes it's hard to trust even the "professional" reviews available online because we simply don't know if their technique in applying the TIM is actually correct or optimal for each TIM they test.
For example, I've found that AS5 requires a different technique (i.e., how to apply it, how much of it, etc.) compared to Shin-Etsu or MX-2. When I used just one way of putting it on the IHS for all three products, there were noticeable differences between all three. But when I started experimenting and testing different methods in applying the various TIMs, the results were all different, which suggests that there are optimal ways to use these things.
Interestingly, when applied in the optimal fashion, these TIMs are more or less created equal... Any variances in reported temps are small (1-2 degrees C at most on spike readings, almost no real variation on consistent readings) as to be insignifcant.
Just some food for thought...