I have not tried xampp, but I have tried EasyPHP and wamp server, and, of the two, I prefer wamp. The reason is that, as far as I am aware, EasyPHP can only be accessed as "localhost" (i.e. from the same machine it is running on. Whereas, wamp, by default, has the same limitation, but can easily be configured to allow access from other machines in your local network (if you have one).
Postscript: Local network access can facilitate testing on different screen resolutions.
