Personally i chose kings over all my other offers and dont regret it one bit, what does upset me though is all the presumptions people have over university in london.
Firstly we DO have a sense of community, and you'd be surprised how easy it is to randomly just bump into people you know around london, especially in the area's near uni. Having a HUGE city to run around also makes our RAG week uber fun, because a few thousand of us have miles and miles of london streets teeming with tourists to badger for cash.
Secondly, its not THAT much more expensive to live in london as long as you dont want to go to musicals etc every night of the week. There are cheap cinemas and student nights in clubs which work out tons cheaper than where i live at home in kent. To top that off you get a bigger student loan which helps to cover the difference in costs in accom. As well as that if you then decide to work in london after graduating you get paid a bit more than elsewhere which allows you to pay back your higher student loans.
But to be honest ive been to brum and i thought it was a pretty nice place, so as the two courses are really different id advise that your friend picks the one they feel most comfortable with, because at the end of the day whether its kings or brum they're sure to still have a great time