Among exchange-traded fund providers, which company offers the cheapest products? Or has the fattest dividends? Or provides the most tried-and-true offerings, or perhaps focuses more on rolling out cutting edge products?

So many questions, and yet so many fund families and individual funds to analyze. In a recent report, S&P Capital IQ took a look at certain fund providers to find themes in how they operate and in the types of funds they offer.

While a number of ETF companies have "compelling equity products that stand out," the report said, S&P Capital IQ's research focused on the four largest ETF providers that it said have the scale and investor awareness to merit an in-depth look at their offerings.

In toto, these fund companies--iShares, State Street Global Advisors, Vanguard and Power Shares--comprised 88% of ETF assets as of June 2012. The report evaluated the fund providers on the number of ETFs offered, average expense ratio, average dividend yield, percentage of ETFs launched in the three-year period ended June 2012, and percentage of ETFs with an overall overweight ranking from S&P Capital IQ.

The data research company uses a bottom-up approach to rating ETFs based on analyzing a fund's individual holdings, and it reserves its top ranking (overweight) for ETFs with holdings that combine attractive valuations and modest risk.

S&P Capital IQ found that BlackRock's iShares funds topped the list with the most funds, the largest asset base and the broadest geographical depth. And, on average, it offered the highest dividend yield among the four largest providers.

But the report found that iShares' significant non-U.S. exposure--in particular, its exposure to Europe--negatively impacted the standard deviations and earnings consistency aspects of its S&P quality rankings.

Among the iShares funds ranked highest by S&P Capital IQ and spotlighted in the report are iShares MSCI Global Energy Producers Fund (FILL) and the iShares S&P Asia 50 Index Fund (AIA), both meriting an overweight ranking.

At State Street, which rolled out the first ETF in 1993 with its SPDR S&P 500 ETF (SPY), just 12 of its 79 ETFs are less than three years old. The company has the fourth most funds in the industry, but ranks second in assets in part because it has many long-standing funds that have attracted significant money.

"If you want diversification, State Street has a lot of great ETFs and they're relatively cheap," Todd Rosenbluth, S&P Capital IQ ETF analyst, said in an interview. "We like a lot of their sector SPDRs."