I always take the Underground in London. Much cheaper - and faster - than taxis.
I took it to get around London and enjoyed it. Much better than driving or taxis. I don’t know how people drive cars in London, much less those double-decker buses. Doesn’t seem like there’s a inch of room on the streets.
But doesn’t it seem a bit ancient and patched? I really enjoyed looking out the windows at the infrastructure - signals, tunnels, cables, etc. Sort of a cross-section of the technology of the London Underground.
Mind the gap!