This book made me think of Ender's Game in a whole new light. In the driver's seat this time we have another brilliant student, possibly even more brilliant than Ender, and you really can't appreciate the commander as much after having read this book. If you want to continue to think of Ender as an incredible leader and a suffering human being, don't read Ender's Shadow. Shadow places Bean at the forefront and shows his contribution to Earth's victory over the Buggers. His personality is strikingly different from Ender.
With less pressure on him, he is more cynical of his teachers and the way battle school is run, but he also has the insight to know the difference between when to rebel and when it actually matters. Despite adult intellect, Ender seems a child next to Bean's self-reflection and vision. He sees through every Battle School mind game, knows far ahead that the simulations are actual battles, and knows what his teachers are thinking before they do. This alternate personality adds another dimension to the story that has already blown us away. Personally, I have yet to read further in the Ender series, but I would call this parallel story a must-read after Ender's Game.
By the way, if anyone is wondering whether they should just read Shadow and not Game, or read them in the opposite order, I would say that I greatly enjoyed my experience reading Ender's Game first and Ender's Shadow almost a year later.