Performance

Both heatsinks performed very well as compared to personal experience with other heatsinks.  Performance of a heatsink is difficult to judge. Do you base your opinion on how cool you CPU stays?  What about the noise factor? Then again, there is price?

    Temperature   

- Tundra 2 - The test bed was kept at a cool temp of 115° F/46° C
- Avalanche -  The test bed was kept at a cool temp of 113° F/ 41° C

*Comment - To my surprise the (aluminum w/ copper core) Avalanche beat the Tundra 2 in this test. This could be the result of removing the thermal pad and using thermal grease instead. Ambient temperature stayed relatively close for both tests.

    Noise Factor      

- Tundra 2 and Avalanche - Neither heatsink was audibly louder than the other and barely distinguishable above the other 6 80mm fans in         my current case.  The fans ran around 4600 RPM.

    Price

- Prices are reasonable for these heatsinks. Prices appeared to settle between $22 for the Avalanche and $40 for the Tundra 2.  The price on the Tundra is a touch high, but you may be able to find it elsewhere at a more reasonable price.

Pros and Cons
-Reasonably quiet
-Effective cooling
-Long power cable
-Heat transfer grease supplied (Tundra 2)

Cons
-Easier mounting clip
-Heat transfer pad on Avalanche

Both of these heatsinks are highly recommended.