I wrote some time ago a post about how to install WordPress on Mac OS X.  I used XAMPP as a basis. But currently I’m using MAMP to host wordpress. 

XAMPP and MAMP are both quite similar. Both of them are self contained so neither touches the default OS X Apache/PHP installation. Both are extremely easy to install. Neither require any command line commands to setup. So both they can safely be tested and removed. You may even install both but you may only run one of them at a time (unless you edit the httpd.conf file for either XAMPP or MAMP and change the port it listens to).

Lately, MAMP seems to get updated more regularly, looks a little more mac-like, has a Dashboard Widget and works without administrator privileges.

On the other hand, XAMPP has many extensions built-in. Also XAMPP components can be started from a GUI or from the command line. MAMP requires the use of the GUI to start/stop it but its GUI does provide a configuration UI (e.g. where the ports can be set).

Conclusion: I’d say MAMP is still the better choice for web designers or PHP programmers who just want to run WordPress or Joomla and make settings using a graphical user interface. If  extensive configuration options is a must, you should consider giving XAMPP a try.