Individual Stocks, ETFs, or Mutual Funds?

I like to purchase individual stocks, but I'm not convinced that they necessarily out-perform market index Exchange Traded Funds ( ETFs) or low-cost mutual funds.  I enjoy doing research on companies, as I've spent much of my  business career evaluating businesses.  It does take work, though.  

That being said, I don't disagree with Warren Buffet's advice to his wife on how to invest his billions upon his passing:

"My advice to the trustee could not be more simple: Put 10% of the cash in short-term government bonds and 90% in a very low-cost S&P 500 index fund. (I suggest Vanguard’s.) I believe the trust’s long-term results from this policy will be superior to those attained by most investors – whether pension funds, institutions or individuals – who employ high-fee managers."

I am somewhat intrigued by the recent emergence of "Robo Advisors", in that they follow a very strict asset allocation model using low-cost ETFs.  I have put a small amount of my assets into one of them, Wealthsimple, and I will write about the performance as I start seeing measurable results.