Similar quoted light output, very different imaging architectures and use cases.
This comparison is useful because the projectors solve different problems. NZ900 is a contrast-first premium cinema design; QB1000 offers substantial colour and white brightness with Epson's 3LCD architecture and a more conventional residential installation path.
If the screen is large or acoustically transparent with meaningful light loss, brightness can shift the result. If the room is exceptionally dark and reflective surfaces are controlled, contrast may become the more valuable resource.
Choose NZ900 for a blacked-out dedicated cinema where native contrast and optical quality dominate. Choose QB1000 when 3LCD colour brightness, mixed use and value are stronger priorities.
Send screen width, gain, throw distance, room finish and viewing priorities.