RE: London Underground, London Overground and DLR
I hate London, wont ever stay there longer than I have to, the Tube is depressing, I witnessed a 'one under' at Kings Cross in 1998 or 1999, and would not use the tube for a long time afterwards, but in London, the tube is the best method of transport as walking and buses would take quite a bit longer.
My experience of the DLR was quite good, found it was efficient and reliable and quite quick as well...
At the end of the day, best part of London is the M1 Northbound or the tracks out of Kings Cross