Alright, let's touch gloves and I want a clean fight.
Comprehensiveness of the Network
The London Underground has 253 miles of tracks in "revenue service" and 275 stations that cover the city well. But the New York Subway has 656 ( ! ) miles of revenue track, and 468 stations along it. This makes NY the clear winner, right? No, not so fast.
A large number of NYC's stations are so close together that they may as well be one station. The IRT's 1 train has a stop at 14th Street, then another four blocks away at 18th Street. Some entire sections, such as most of the A train stations in the Rockaways, have very few riders. Other lines-the 4 and D up in the Bronx, various lines in Manhattan--run parallel to one another, a block or two apart. If the system was built today, noone would design these lines this way.
The NY Subway does not serve the big borough of Staten Island at all ( though there is a subway-like train, the Staten Island Railway, that covers some of it)
London's Underground does one thing with its 275 miles that NY's subway does not do with its 656 miles--it goes right to the airport. Yep, the Piccadilly Line has cheap --if slow--service to Heathrow Airport. And it has taken me to the City, and everywhere else in the London area I want to go.
London's trains have nice cushioned seats, while NY's are made of hard plastic.
You'd think London would win the cleanliness sweepstakes, but you'd be WRONG. I notice a lot more discarded newspapers and other trash in the London trains than I do in NY.
One reason why--there are no waste baskets in the London system, anywhere. This sounds unbelievable, until you hear why--they removed them during the IRA attacks of the 1970s- - 1990s. Couldn't allow for the possibility of bombs being hid there. In the post 9/11 world, they won't come back soon.
Most of the passengers in London are well-behaved, but most of the passengers in NY are fine, too.
Advantage: New York
Will finish this up on Saturday night. Gotta go.