For me it is. I think tomb raider had higher lauch sales, but there is a massive fanbase for the TR franchise.
I just hope that Infinite sells enough to cover the $200 million they spent developing and marketing the game. I read an article that worked out they would have to sell 8 million copies of the game to break even. Which doesn't sound like a lot when you think there are 60 million peeps in the UK alone. But Bioshock 1 only sold 4 million as of March 2010 according to Wikipedia.
Problem with tomb raider is it was cool to play through but I was quite suprised how quickly it ended... Once it is over there is no real replay value after you have done the few optional tombs... Shame it did not have more content or replay value because it was fun. Bioshock however looks like something I would like to play through more than once just for the fun of it.