Somehow the locations for the brand name hotels do not appeal to me as I like to stay near local night markets or the old towns. Often time, the brand name hotels are in the city centers. That said, I would not stay in $20 hotels. I did once in Hanoi. It is 8+ reviews on Tripadvisor. What a disaster! However, I have stayed at a $70 a night hotel in Saigon and it was better than the standard Holiday Inn Express or Hampton Inns in the US but not much better.

For one or two nights, why not, as long as you have AC and private bath.