The "banking meets google" schtick is laughable. Training is non-existent and senior management in most departments (not all) are never around. When they are, they regularly miss meetings and conference calls, especially important ones. Projects are never delivered or advanced in a timely manner, so don't expect any support from that aspect.
It speaks volumes that this company has only been in the US for less than 4 years and has already closed down 3 offices and is constantly recycling people at the whim of the CEO. There is little to no job security here unless you are buddy-buddy with someone in senior management, otherwise make sure to keep your resume updated at all times.
Forget about professional development or any semblance of leadership, unless you are in the London office. Hard work will likely not get you far at this company, but getting smashed with your boss on a weekly basis will....again, that should tell you something.
World First (USA) has very few components that you would find in a legitimate company. "Beer thirty" is not something to hang your at on and isn't even unique anymore.
If you are straight out of college and want to work in a "party" atmosphere, World First might be the place for you, but remember that you are disposable and they will dispose of you without blinking an eye, If you are a professional trying to advance your career, stay away from this place.