Reddit mentions of Your Complete Guide to Factor-Based Investing: The Way Smart Money Invests Today

• A John Bogle Indexing Book or any book that covers indexing and why its more prudent than active management. I know this isn't what you asked, but the rest of the points on my list will fall apart without a solid foundation.
  
  
• Index Fund Advisors website For an introduction to both indexing and academic investment factors. An absolute ton of videos and articles, and even a Risk Capacity survey (if you fill out the survey, they will email you about wealth management, but there is a ton of free information on the site).
  
  
• Paul Merriman's website for factor based investment strategies and portfolios. He also has a weekly podcast.
  
  
• Larry Swedroe's website and his books for more factor-based investment advice. My favorite book is this one
  
  
• Vanguard video webcasts for coverage on a myriad of investing, economic, and financial planning topics, with CFAs, CFPs, and other professionals.

Nobody knows. Maybe the S&P will do the best. Or it might be VTSAX, small value stocks, foreign stocks, or emerging markets. That's why you diversify.

Over the long haul, small stocks tend to outperform large stocks, and value stocks to outperform growth stocks, so the S&P isn't even the most likely to win. See for example this book by Berkin and Swedroe.