Warren Buffett has averaged over 20%/yr.

George Soros and Jim Rogers averaged over 30%/yr for the first 30/35 years of the life of the Quantum fund. I don't know how it has done since. A lot of his best traders/speculators that he employed gradually left him. Whether he found new talent to replace them, I don't know.

Bob

I recall reading a comparison of Soros and Buffett with respect to their annual returns and one issue was that Buffett has had worse tax exposure than Soros ever had, since Soros was operating out of a haven.

The other factor would be that Soros was more of a financial speculator, whereas Buffet is more of a corporate investor. The risks and returns are higher in speculation, so you would need to look at the volatility of the Quantum fund to see whether it indicates the higher returns.