There are more master limited partnerships on the market than ever before, which means investors have a lot of ground to cover if they want to find the best one. It can be helpful to have quick summaries on a stock before you spend hours pouring through filings. In this video, Fool.com contributor Aimee Duffy talks to Tyler Crowe about what investors should know about Northern Tier Energy (NYSE: NTI), Eagle Rock Energy Partners (NASDAQ: EROC), and Enterprise Products Partners (EPD 0.22%) before they commit to hours of research.