Recent years have bucked trends in the perennial growth vs. value competition. Value tanked during the Credit Crisis of 2008 when it should have outpaced growth, and now with a confirmed economic recovery value is gaining when it should be ceding ground to growth. There is contradictory evidence for whether can sustain its run.
Historically the argument for value has been that it is inherently less volatile and more defensive in a bear market. But over the past three years and especially during the worst of the stock market crash, iShares Russell 3000 Value ETF (NYSEArca:IWW) fell behind its growth counterpart, iShares Russell 3000 Growth ETF (NYSEArca:IWZ):

And now that a tepid recovery is confirmed value is jumping ahead:
Much of this behavior can be explained by heavy exposure to financials. Financials constitute over 20% of company holdings in a typical value ETF, compared to under 10% in a typical growth ETF. Financials took it on the chin badly during the Credit Crisis of 2008. As financials recover, the "banking effect" should mostly dissipate in 2010 or 2011. Value is not a direct way to play a rebound in banking directly, however. Sector ETFs are more suitable.
Long periods of dominance of one over the other are the norm for value/growth, and the longer one has been on top the more likely it will fall relative to the other. It is not unreasonable to ask whether value can sustain further advances. The answer is debatable.
What makes value attractive now is that it has trailed for some time, and it should absorb future economic shocks better than growth. This is clearly a period of shocks. Another item in its favor is the approximately 1% additional dividend yield its churns out. Investors are seeking income in the current low-yield environment.
What makes value less attractive now is the tepid recovery of the US economy (and indeed the world economy). Recovery traditionally favors growth. Also, valuations for growth are at historically moderate levels compared to value. IWW sports a PE of about 14 while IZZ only carries 16. It normally costs a bit more for growth relative to value.
Value enthusiasts once pointed to research by Fama and French as evidence that value performs better than growth AND at lower risk. In the 1990's when the data looks most convincing, value started a long period of underperformance. Fewer academics today claim a free lunch with value.
A typical value ETF will split up an index and take firms with a low projected price-to-earnings ratio (P/E), earnings growth, price-to-book ratio, and revenue growth, but a high high dividend yield.
Many fine plain vanilla ETFs serve value at low cost. They are differentiated primarily by the size of firms they address:
The above products have reasonable fees (with Vanguard as usual leading the pack) and are based on well-regarded, modern, capitalization-weighted indexes. SPDR uses Dow Jones Wilshire indexes, while iShares deploys both Russell and S&P indexes, and Vanguard depends on MSCI. It is useful that most ETFs in each line are complementary and have no overlap. By sticking to one product line, an investor can overweight one asset class with clarity and precision. Among the exceptions is iShares' IWW which is a nearly total market product, Vanguard's VTV which is the sum of MGV and VOE, SPDR's ELV which overlaps other Wilshire ETFs in mid-cap and likewise iShares' IWS.
There are also funds through Rydex and Morningstar which claim to more accurately capture value as a concept in their index methodologies. They tend to be a little more expensive:
There are also several ETFs based on proprietary enhanced or fundamental indexes. These funds sometimes deliver higher returns, sometimes lower.
Fundamental Value ETFs
And finally there are short and leverage value ETFs suitable for speculative traders looking for a short-term play:
Short/Leverage Value ETFs