Marriage isn't easy -- especially between companies in a post-recession era. Here are the top five M&A deals from the past five years. Vodafone's $130 billion transfer of its wireless unit to Verizon Communications earlier this year worked out in both companies' favors. Vodafone shareholders received $84 billion, reward for 14 years of witnessing shrinking market capitalization -- while the wireless business enhanced Verizon's ability to build new networks with advanced technologies. Other top M&A deals in recent years include last year's union between US Airways and American Airlines' parent AMR Group, which created the world's largest airline, and Express Scripts' merger with Medco Health in 2012, which improved the health care space.