There are 2 angular cli packages available on npm:
angular-cli which is currently at 1.0.0-beta.28.3
@angular/cli which is currently at 1.0.0-beta.31
@angular/cli is the new package, which name is according to another Angular 2 modules names like @angular/common, @angular/router and so on.
@angular/cli
@angular/common
@angular/router
And also @angular/cli requires Node 6.9.0 or higher, but angular-cli requires Node 4 or higher. So @angular/cli with Node 4 will not work.
Node 6.9.0
angular-cli
Node 4