The Symfony Installer is the best way to create a new project with Symfony 2
and Symfony 3. But as of Symfony 4, you can use Composer, plain and simple.
It’s more standard, more ubiquitous, and that’s one less Symfony specific tool
Like other announcements we have made recently, this blog post officially
announces that the Symfony Installer won’t be developed anymore. Bugs will
still be fixed and its end of life is scheduled for November 2020 as this is
when Symfony 3.4 will not be supported anymore.
Composer for the win!