Gigadrive

Platform.sh has great out-of-the-box support for PHP apps (especially Symfony, as it was made by the same people). Elastic Beanstalk does not have a lot of compelling PaaS features like Platform.sh. There, you have to install a lot of PHP extensions manually for example, while Platform.sh just handles it for you based on your config. Elastic Beanstalk also has terrible version updates (see link).

Easier setup and integration for PHP based applications. Azure App Service requires a lot of extra configuration, while AWS Elastic Beanstalk has most things set-up out of the box. On top of this, Azure is much more expensive.