I think using autoload is a more of a pain in the neck than just using require_once method.
1. The original coding stardard used for naming classes used to be like this:
ControllerUserGroup and now because of zend people have changed to Controller_User_Group.
You should not forced to rename your classes. A better way of autoload classes should have been thought up before releasing autoload.
2. You can not have gaps in your filenames.
Autoload will try to look for controller/user/group.php
Even Ruby-On-Rails uses a require method.
Does anyone else here prefer to use require_once instead of __autoload?