Investors with an interest in REIT and Equity Trust - Retail stocks have likely encountered both Tanger Factory Outlet (SKT) and Equinix (EQIX). But which of these two stocks presents investors with the better value opportunity right now? Let's take a closer look.Everyone has their own methods for finding great value opportunities, but our model includes pairing an impressive grade in the Value category of our Style Scores system with a strong Zacks Rank. The Zacks Rank is a proven strategy that targets companies with positive earnings estimate revision trends, while our Style Scores work to grade companies based on specific traits.Tanger Factory Outlet has a Zacks Rank of #2 (Buy), while Equinix has a Zacks Rank of #3 (Hold) right now. The Zacks Rank favors stocks that have recently seen positive revisions to their earnings estimates, so investors should rest assured that SKT has an improving earnings outlook. But this is just one piece of the puzzle for value investors.Value investors analyze a variety of traditional, tried-and-true metrics to help find companies that they believe are undervalued at their current share price levels.Our Value category highlights undervalued companies by looking at a variety of key metrics, including the popular P/E ratio, as well as the P/S ratio, earnings yield, cash flow per share, and a variety of other fundamentals that have been used by value investors for years.SKT currently has a forward P/E ratio of 7.91, while EQIX has a forward P/E of 19.96. We also note that SKT has a PEG ratio of 0.95. This figure is similar to the commonly-used P/E ratio, with the PEG ratio also factoring in a company's expected earnings growth rate. EQIX currently has a PEG ratio of 2.16.Another notable valuation metric for SKT is its P/B ratio of 2.86. The P/B ratio is used to compare a stock's market value with its book value, which is defined as total assets minus total liabilities. For comparison, EQIX has a P/B of 4.96.These are just a few of the metrics contributing to SKT's Value grade of B and EQIX's Value grade of D.SKT stands above EQIX thanks to its solid earnings outlook, and based on these valuation figures, we also feel that SKT is the superior value option right now. Special Report: The Top 5 IPOs for Your Portfolio Today, you have a chance to get in on the ground floor of one of the best investment opportunities of the year. As the world continues to benefit from an ever-evolving internet, a handful of innovative tech companies are on the brink of reaping immense rewards - and you can put yourself in a position to cash in. One is set to disrupt the online communication industry. Brilliantly designed for creating online communities, this stock is poised to explode when made public. With the strength of our economy and record amounts of cash flooding into IPOs, you don’t want to miss this opportunity.>>See Zacks’ Hottest IPOs NowWant the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Tanger Factory Outlet Centers, Inc. (SKT): Free Stock Analysis Report Equinix, Inc. (EQIX): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research