The Vanguard Mega Cap Growth ETF has outpaced the Vanguard S&P 500 ETF in 1-year and 5-year total returns but carries a higher expense ratio and greater sector concentration.The Vanguard Mega Cap Growth ETF (MGK +1.11%) delivers stronger recent growth but higher risk and a steeper price, while the Vanguard S&P 500 ETF (VOO +1.42%) stands out for its low cost, broad diversification, and much higher payout.Both funds track large-cap U.S. equities, but the Vanguard Mega Cap Growth ETF, like the name implies, f ...