Sales figures in the US have shown that Guitar Hero outsold its rival Rock Band by over one million copies in November.
However, while that may make it seem Activision Blizzard's game is in the lead in overall sales, investment analyst Ben Schachter reports a different story.
Having looked into it, Schachter reports that Guitar Hero sales are in decline compared to last year, while Rock Band's are increasing sharply.
However he also noted that overall, the US market for music games first kicked off by Guitar Hero seems to be in decline.
Figures show that over 1.7 million Guitar Hero games for all formats were sold in the US in November, 978,000 of which were of World Tour. This compares with 628,452 copies of Rock Band and Rock Band 2 combined.
However, comparing these sales to November 2008, Guitar Hero sales were down 25.3%, and Rock Band's were up 64.7%. All in all though, the combined sales of both games fell 12% from last year.
"This will fuel concerns that the genre is past its peak", he said. "With Activision and others sure to bring new innovation to the genre next year we can't count it out, but it almost certainly won't be the growth driver it has been over the past two years".