Selecting the best high-yield stocks from the bargain bin tends to involve a balancing act. Companies that offer big dividends and trade at low earnings multiples often do so because their underlying businesses face challenges that stand in the way of sustainable earnings growth -- setting up situations in which investors might be tempted into buying businesses that fall short as long-term investments. While the reality of that dynamic should be kept in mind, it's also true that buying the right dividend stocks at the right prices is one of the most reliable ways to power your portfolio to market-beating returns.