What do you like best?
This framework is a set of components that allows to makes it a fullstack framework with a lot of best practices inspired from other successful languages.
You can manage bundles (which are packages) in your application to decouple features and structure your code to be maintanable and clear.
There is also a lot of bundles offered by the community that covers many functionalities so you can reuse a great set of libraries in your applications. Community is really active so the framework is evolving a lot everyday.
The framework is really well tested with unit tests and you can add unit tests and functional tests (with Behat) in your project easily to have a high quality project.
What do you dislike?
Dependencies can sometime be quite heavy when building the project and projects can depend a lot of external libraries. Hopefully, these libraries can be overrided in the framework.
Also, it can be complex to manage some frontend tools (like Gulp, Bower, ...) to manage both Symfony assets and a frontend project assets.
Recommendations to others considering the product
This is the best PHP framework that exists actually and this framework can really heading in the right direction.
What business problems are you solving with the product? What benefits have you realized?
I develop web applications for large business companies so there are business applications and also ecommerce websites with a lot of data.
I also develop APIs to expose data in order to use them on frontend applications so Symfony is the backend application part. Indeed, Symfony has a really great model based on request processing that returns an HTTP response and also provides a great Security component that allows you to filter by IP adresses or use some other authentications methods: HTTP basic, JWT, accounts stored in database, etc... really easily.