Investors interested in Insurance - Property and Casualty stocks are likely familiar with Allstate (ALL) and Berkshire Hathaway Inc. (BRK.B). 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 proven Zacks Rank puts an emphasis on earnings estimates and estimate revisions, while our Style Scores work to identify stocks with specific traits.Allstate and Berkshire Hathaway Inc. are sporting Zacks Ranks of #1 (Strong Buy) and #3 (Hold), respectively, right now. The Zacks Rank favors stocks that have recently seen positive revisions to their earnings estimates, so investors should rest assured that ALL 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.The Style Score Value grade factors in a variety of key fundamental metrics, including the popular P/E ratio, P/S ratio, earnings yield, cash flow per share, and a number of other key stats that are commonly used by value investors.ALL currently has a forward P/E ratio of 7.42, while BRK.B has a forward P/E of 23. We also note that ALL has a PEG ratio of 0.99. This popular metric is similar to the widely-known P/E ratio, with the difference being that the PEG ratio also takes into account the company's expected earnings growth rate. BRK.B currently has a PEG ratio of 3.29.Another notable valuation metric for ALL is its P/B ratio of 1.18. Investors use the P/B ratio to look at a stock's market value versus its book value, which is defined as total assets minus total liabilities. By comparison, BRK.B has a P/B of 1.31.These metrics, and several others, help ALL earn a Value grade of A, while BRK.B has been given a Value grade of C.ALL sticks out from BRK.B in both our Zacks Rank and Style Scores models, so value investors will likely feel that ALL is the better option right now.Want 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 The Allstate Corporation (ALL): Free Stock Analysis Report Berkshire Hathaway Inc. (BRK.B): Free Stock Analysis Report To read this article on Zacks.com click here. Zacks Investment Research