Commentary series include book-length commentaries on the individual books or sections of the Bible. Not every volume within a series is of equal value. Do not let yourself be locked into one series. Become familiar with commentaries from multiple series.
Book reviews are a good place to evaluate individual commentaries within a series. (For example, consider the Review of Biblical Literature.) But realize that no review is value-free! Read reviews, but read them critically.
Different commentaries (whether a series or an individual volume) often represent different perspectives; some will be broad, some will have a very specialized focus. Read commentaries to get a variety of theological, scholarly, and cultural perspectives. While you might start to favor one commentary over others, be open to encountering other voices.