I have recently upgraded one of work project to PHP 7. What a bliss... Just by upgrading we have managed to reduce response time for Symfony based API from 100ms to 75ms (25% boost). (Note: responsibility of the decreased timing might also be from some updated libraries and drivers)
I have also managed to upgrade the present blog to the new PHP version and a similar improvement was observed.
Other major improvements from my perspective:
- Strong type return methods (this can help increase the code quality and will help resolve some bugs in some early stages). I was a bit disappointed that overloading is still not available.
- Syntax errors are now catchable