Harmonix has successfully managed to transform Rock Band into a great music platform, with just about 600 songs already available across all games, track packs, and downloadable content. While Activision is choosing to spam the Guitar Hero name by saturating the market with incremental releases, Harmonix has been diligent in weekly song releases and making disc-based track packs available as an alternative.
Pwn or Die has a great article featuring graphs that break down where songs come from, dominant genres, difficulty levels, and much more. It’s interesting to analyze the data and look for trends or patterns in how Harmonix chooses the type of songs to release. I certainly don’t mind the difficulty imbalance, but I hope they start to even out genre and decade song distribution in the future.
Whatever they’re doing, I hope they keep doing it because it’s working. Only Harmonix could make Snoop Dogg, the Dixie Chicks, and the Beatles make sense all under one roof.