Never been to London but Los Angeles greater than New York...
New York is dope, on aggregate it deserves its reputation but it is slightly overrated. It's age and historical heft gives it the one up on LA---->LA had 100,000 people in 1900. Just think about that for a second. That was only 122 years ago...
In less than a century Los Angeles caught up to NY in nearly anything, and I've been on this for years, anything you can do in NY that matters, you can do in Los Angeles...
So I'm not sure how London compares but NY is overinflated online stateside, and it doesn't have to be. But when you meet folk who've been to both, the typical reaction is right down the middle 50/50, but when you're online you get way more NY riders in part because many people haven't experienced both...