I think these are basic tents , bathtub groundsheets, using 3000HH material , and appear to be oversized , and yes cheap . Are they any good ? Who knows ? They are probably imported for a specific retailer as their special line .
I'd personally rather go for a tent from a well-known manufacturer, there are bargains to be had if you shop around and lots of advice and info will be forthcoming if you post your requirements / budget etc on these boards.