Vanguard Dividend Appreciation ETF (VIG 0.50%) focuses on U.S. companies with a record of growing their dividends year over year, while ProShares S&P 500 Dividend Aristocrats ETF (NOBL 0.79%) invests in a diversified group of U.S. stocks. VIG casts a wider net with hundreds of holdings, while NOBL targets S&P 500 constituents, using an index with at least 40 equally weighted stocks and sector caps. Here is how the two compare on key metrics.Snapshot (cost & size)MetricNOBLVIGIssuerProSharesVanguardExpense r ...