Especially their refractors, but also their larger EQ mounts are pretty ubiquitous because of their performance and price. Don't tend to hear many complaints about their Dobs either
Incidentally, Skywatchers parent company Synta also owns Celestron, better known for the SCTs which are more complex and not so easy to make consistently well...but according to other sources, the product is consistently better now (with all their production now in China) than previous times.