Hello.. AOSmith is american, and not chinese.
This company gives good products and is more reliable than indian brands. Atleast they are very long lasting. As far as i know, they give longer warranty also: 5 or 10 years.
by the way, problems in servicing may be because of local service people. i am from hyderabad and i have seen problems in services from ifb, aquagaurd, whirlpool, while lg, onida are good. its not because of company but local franchise that take up servicing contract. so better escalate to AOsmith higher authority and things will start moving