diff --git a/README.md b/README.md
index 0a4f0af..0658d78 100644
--- a/README.md
+++ b/README.md
@@ -88,7 +88,7 @@ There is also a `test:quick` Robo task which excludes slower tests, and a `test:
 
 ### Test coverage
 
-Computing the coverage of tests can be done by running `./robo coverage`. Either [phpdbg](https://php.net/manual/en/book.phpdbg.php) or [Xdebug](https://xdebug.org) is required for this. An HTML-format coverage report will be written to `/tests/coverage/`.
+Computing the coverage of tests can be done by running `./robo coverage`, after which an HTML-format coverage report will be written to `/tests/coverage/`. Either [Xdebug](https://xdebug.org) or [phpdbg](https://php.net/manual/en/book.phpdbg.php) is required for this. Xdebug is generally recommended as it is better maintained, though phpdbg is significantly faster. If using Xdebug, the extension need not be enabled globally; PHPUnit will enable it when needed.
 
 ## Enforcing coding style