Well diversified portfolio all day long. First across asset classes, then strategies. Only free lunch to bring up your risk-adjusted returns. And with leverage applied, you can bring up your absolute returns.
The owner of the company that my dad worked for used to say that diversification is for those who aspire for mediocrity. he died being worth 9 billion dollars (starting with nothing).
The more stocks you own the more your results trend toward average. Diversification hides your mistakes.
If your diversification includes a bunch of quality stocks and a bunch of filthy stocks, end of the day, you earn nothing or negative. If your diversification includes a bunch of quality stocks and a bunch of good stocks, end of the day, you earn $$$$$.