Based on the aggregated intelligence of 180,000-plus investors participating in Motley Fool CAPS, the Fool's free investing community, the Vanguard Mid-Cap ETF (AMEX: VO) has earned a coveted five-star ranking.

With that in mind, let's take a closer look at Vanguard Mid-Cap and see what CAPS investors are saying about the ETF right now.

Vanguard Mid-Cap facts

Inception January 2004
Total Assets $3.28 billion
Investment Approach Seeks to track the MSCI US Mid Cap 450 Index, which measures the performance of a diversified group of companies with market capitalizations of approximately $1 billion to $8.5 billion.
Expense Ratio 0.12%
1-Year / 3-Year / 5-Year Return 4.2% / 23.3% / 1%
Top Holdings with High CAPS Interest (at least 1,000 Active Picks) and Portfolio Weight Green Mountain Coffee Roasters (Nasdaq: GMCR) (0.62%)
Whole Foods Market (Nasdaq: WFM) (0.51%)
Chipotle Mexican Grill (NYSE: CMG) (0.49%)
Dividend Yield 1.2%
Alternatives iShares S&P MidCap 400 Index (NYSE: IJH)
SPDR S&P MidCap 400 (NYSE: MDY)

Sources: Morningstar and Motley Fool CAPS.

On CAPS, 94.5% of the 91 members who have rated Vanguard Mid-Cap believe the ETF will outperform the S&P 500 going forward. These bulls include JONATHANCO and acegdl007.

Having gotten on board a couple of years ago , JONATHANCO succinctly summed up the bull case:

Midcap beats large cap in most economic environments. Midcap is the sweet spot of [A]merican innovation. Large enough to be credible business, small enough to be flexible and innovate.

Vanguard Mid-Cap, in particular, sports a cheap expense ratio of 0.12%. That's lower than that of other midcap ETFs like iShares S&P MidCap 400 (0.21%) and SPDR S&P MidCap 400 (0.25%).

CAPS member acegdl007 elaborates on the outperform argument:

ETF version of its Mid Cap mutual fund. Vanguard has a great reputation for offering attractive funds and ETF's with some of the lowest management costs and fees. This is a great ETF/fund to include in a 401k portfolio that will add a comfortable dose of risk with potential for good growth in the long term.

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