I'm not a huge fan of bmi's 'look'. The watery blue website colours just looks weak, whereas the black background really stands out, and as it is high contrast presumably good for the visually impaired, but as mitchja says, it's only the front page that's changed, which makes the page change very jarring.
Websites are important things - I remember when I was checking flights for a friend last year, we went through all of them and they were all very professional, a bit dull, and then we both laughed at the 'Hello Gorgeous!' on the VS website. Guess who they booked with?