Hello,
actually we don't say it is any better. We like the CAGR+MaxDD and CAGR+R
2 the most.
But these are combinations (vectors) of measures, we were also in need of having some single measure (single number) to cover both system performance and profit distribution over time. And this is why we came with the system score.
We use different measures like Sharpe Ratio, too.
There is no literature because we came with this concept ourselves. It is basically a CAGR weighted by equity shape/ profit distribution. Time will show if it is useful or not