"Horrendous!" "truly awful"? Can you elaborate on what exactly is wrong with OsmAnd's UI to elicit such a strong reaction? I use it myself and don't have any problems with it. It seems about the same as any mobile app with comparable complexity.
When I finally get the results of my query for "Hammersmith" it tells me that 309km away (some mistake, more like 3.9km) there is "Subway Station District Line;Hammersmith & City Line", and then the same result repeated around 150 times some with slightly different naming, and at varying distances from 309-328km away before it gets to other results in Hammersmith.
And you are trying to use this on a phone in the rain, you just give up and go back to google maps even though the data is worse.
EDIT: And if you select one of these it appears to be in Barking, as it found every station on the Hammersmith and City Line, although that is not 300km long.