What are the advantages and the disadvantages of a merger?

As part of the financial planning process, a common practice in the corporate finance world is restructuring through the process of mergers and acquisitions (M&A). It seems that on a regular basis, investment bankers arrange M&A transactions, forming one company from separate companies. What are the advantages and the disadvantages of a merger? In your response, provide an example of either – a merger that was successful, or one that was unsuccessful. (title page, abstract and reference page not included in word count)