Southall is still a very rundown area IMHO, and has a very predominant Sikh/Hindu/Muslim (edit!) population (so shops are mainly designed with them in mind) . Not really somewhere where I'd live, although it is slowly improving and being on CrossRail will help further.
Overall I find this article one of those puff pieces. Yes London is a great city, yes I love living here and I have no plans to return back to Oz to live for a long time. The nightlife is great, the public transport system is one of, if not the best in the world, and dining and entertainment options are extensive. Location wise it's in a great spot with Europe on the doorstep, and a short hop to America.
However, the downsides are underplayed in the article. Price of housing/rentals for anything decent is crazy. Immigration is too high (and yes, I'm saying that as an immigrant!), leading to stress on infrastructure and traffic woes. The massive amounts of apartments being built, mostly aimed at very rich overseas investors (who never live there, and don't rent them out) is seriously stuffing up the property market. There is a massive disparity between classes and it is quite easy to see. Cost of living is going up, with restaurants getting a lot more expensive over the last few years, although groceries are still well priced. Pollution levels is still a major concern. It is not a good place to bring up children.
You do need a decent wage to live in London comfortably, and unless on extensive Government benefits or some other subsidy (living with parents, or in a 6 person share house), will struggle earning < £40000 pre-tax IMHO.
Like Australia, it isn't the land of milk and honey that many people incorrectly think it is.