Bitcoin price on Jan 2nd, 2012: $6.18
Bitcoin price on September 20th, 2017: $3,850
Total return between the two dates: 62,197.73%
S&P 500 price on Jan 1st, 1871: 4.44
S&P 500 price on September 20th, 2017: 2,505.94
Total return between the two dates: 56,340.09%*
*Does not factor in dividends
Feel free to post your calculations if you want to be more accurate like factoring in dividends or inflation. Also I didn't go back to the very beginning of bitcoin's start since I am not exactly sure when the first exchanges started.