I live in London, carry an A to Z, and bought this map to see what it was like.
1)Easier to get an overview of where you are than the usual tourist maps of London, or the A to Z
2)The soul places listed are IMHO interesting places to go and get a feel of different aspects of London at different times in its history, and few of them are anything like tourist traps.
3) Easy to open out and hold, even with quite short arms.
4) Easy to quickly put away, without fear of damaging it.
It shows a lot of interesting places which even a born Londoner (like my husband) wouldn't be familiar with, and (hallelujah!) it includes north Lambeth, down as far as Vauxhall. However, the map doesn't extend eastwards past Shoreditch, Hoxton, the temple of Mithras, and Bermondsey Street.
I'd happily give a map like this to a visitor and let them take it home afterwards, but I'd also lend them an A to Z.
N.B. if you buy this map, do follow the instruction to crumple the map before use - it makes it more pliable and easier to stuff in the pouch.