William Blair analyst Jim Breen published a bull/bear report on Gogo, calling the stock one of the more controversial names that his firm covers. Bulls point to Gogo's leading incumbent position with many of the top airlines, improved technology and low industry penetration, while bears point to the company's low margins, close to $800M in debt and convertible bonds, and $100M-plus cash burn over the next couple of years, Breen tells investors in a research note. The analysis keeps the analyst bullish on shares of Gogo. Cost management and the margin structure will "improve greatly" as international revenue begins to grow and domestic installation of 2KU improves revenue per plane, Breen argues. He keeps an Outperform rating on the shares. The provider of in-flight Internet connectivity closed yesterday at $8.40.