Green Day includes 47 songs (some are combined) covering the group's career from the mid-90's until present day. As with any release, there are songs that didn't make the cut, so hardcore fans will undoubtedly uncover some disappointment. As a casual fan, I liked the mix of songs I knew and those I really didn't. What really sticks out about the selection is how well they work within the context of Rock Band's gameplay. A lot of eyebrows were raised when the game was originally announced, but now I see why Harmonix went with the group.
As a side-note, songs are exportable into Rock Band (and presumably Rock Band 3) for $10.
Venues and visuals feel very light compared to the rest of the presentation. With The Beatles Rock Band, Harmonix showed a willingness to go beyond stage presentation. It's disappointing they didn't show the same willingness with Green Day. Considering the narrative structure of Green Day's recent albums, it seems like something could have been done. At the very least, Harmonix could have tried to lean on concepts from the Broadway show.