Arctic Silver has been the reigning champion in thermal interface materials for a pretty long time. This has let them control the prices they charge for their product with no real threats from other companies. That may change in the future.
ESG Associates has produced a product that is competitive in its level of performance. Even though it didn't beat down the reigning champ, it did manage to remain very close and is doing so at a greatly reduced cost to the end user.
Bottom line...If you're playing with a rig and have plans on overclocking in your future, then you should consider Nanotherm as a viable choice in TIM's.
Many applications in a single syringe
Slightly higher temps at 100% CPU usage
Rating - 8.5/10