The short version
Bangkok Noi is for readers who want old Bangkok’s canals, hospitals and ordinary neighbourhoods rather than a branded riverside lifestyle. It is close to the historic centre, but the experience is distinctly west bank: narrow lanes, local markets and water routes sit beside the large Siriraj complex and busy connecting roads.
The useful parts
Bang Khun Non and Fai Chai are the practical anchors. Around Fai Chai, the Blue Line makes the district much easier to use than it once was. Towards the canals, the atmosphere changes quickly. Bangkok Noi Canal still gives the area its shape, and a boat trip reveals temples, workshops and houses that a road journey misses. The canal edge is atmospheric, but not automatically convenient for groceries or school runs.
Siriraj gives the eastern side a constant institutional presence. That means useful services and transport, along with ambulances, visitors and traffic. Away from the main roads, the district can be surprisingly domestic. Check the route home after dark and in rain, especially if a listing is deep in a soi.
Getting around
Fai Chai MRT is the obvious rail connection, with buses, taxis and boats doing the rest. The Blue Line links the area to Hua Lamphong and the newer west bank stations. A car is unnecessary for many households near Fai Chai, but it is useful if daily life crosses the river or depends on hospital and school journeys.
My verdict
Bangkok Noi suits someone who notices the difference between a historic neighbourhood and a themed heritage quarter. I would choose it for local texture and access to the old city, while accepting uneven pavements, occasional congestion and a less predictable evening than central Sukhumvit.