docs: Highlight the differences with Amphp/Reactphp (#276)

Author: theofidry

README.md

@@ -12,6 +12,7 @@ This library supports the parallelization of Symfony Console commands.
   - [Batches](#batches)
   - [Configuration](#configuration)
   - [Hooks](#hooks)
+- [Differences with Amphp/ReactPHP](#differences-with-amphpreactphp)
 - [Contribute](#contribute)
 - [Upgrade](#upgrade)
 - [Authors](#authors)
@@ -266,6 +267,30 @@ The library supports several process hooks which can be configured via
 *: When using the `Parallelization` trait, those hooks can be directly configured by overriding the corresponding method.
 
 
+## Differences with Amphp/ReactPHP
+
+If you came across this library and wonder what the differences are with [Amphp] or [ReactPHP] or other potential
+parallelization libraries, this section is to highlight a few differences.
+
+The primary difference is the parallelization mechanism itself. Amphp or ReactPHP work by spawning a pool of workers and
+distributing the work to those. This library however, spawns a pool of processes. To be more specific, the differences
+lies in how the spawn processed are used:
+
+- An Amphp/ReactPHP worker can share state; with this library however you cannot easily do so.
+- A worker may handle multiple jobs, whereas with this library the process will be killed after each segment is
+  completed. To bring it to a similar level, it would be somewhat equivalent to consider the work of handling a
+  segment in this library as a Amphp/ReactPHP worker task, and that the worker is killed after handling a single task.
+
+The other difference is that this library works with a command as its central point. This offers the following advantages:
+
+- No additional context need to be provided: once in your child process, you are in your command as usual. No custom
+  bootstrap is necessary.
+- The command can be executed with and without parallelization seamlessly. It is also trivial to mimic the execution of
+  a child process as it is a matter of using the `--child` option and passing the child items via the STDIN.
+- It is easier to adapt the distribution of the load and memory leaks of the task by configuring the segment and batch
+  sizes.
+
+
 ## Contribute
 
 Contributions to the package are always welcome!
@@ -293,8 +318,10 @@ See the [upgrade guide](UPGRADE.md).
 All contents of this package are licensed under the [MIT license].
 
 
+[Amphp]: https://amphp.org/
 [Composer]: https://getcomposer.org
 [Bernhard Schussek]: http://webmozarts.com
+[ReactPHP]: https://reactphp.org/
 [Théo Fidry]: http://webmozarts.com
 [The Community Contributors]: https://github.com/webmozarts/console-parallelization/graphs/contributors
 [issue tracker]: https://github.com/webmozarts/console-parallelization/issues