People criticize companies for sending their titles out to die by releasing at the same time as other mega-titles but the companies have already done their research. It may be outdated, though. They stated long ago that releasing a game in the last three months of a year greatly improves sales. In fact, sales of games and consoles from Oct-Dec typically exceed game sales of the other nine months combined.
That's why we always see games like Rayman Origins or Beyond Good and Evil going up against the big guys. Or Gears of War 3/Uncharted releasing at the end of the year to maximize profits. Gaming media have long complained about this stating "Gamers like to play games all year around" or "Why not release games in the summer?". Only recently, with great games being delayed or with titles like Mass Effect 3 and Red Dead Redemption have companies seen that huge games can do huge numbers releasing early in the year. Still seems that most prefer to launch at the end of the year for the guaranteed sales. Someone has to lose, though.
Despite the lukewarm reviews, I think Sonic is still a big name and it will go on to sell decently.