Well real quick, AUTOLOAD is a brief section in his live presentation that you can view from typing perldoc perltoot and perltooc. The way he uses it, it definately enhances efficiency.
Tradez "Every official that come in
Cripples us leaves us maimed
Silent and tamed
And with our flesh and bones
He builds his homes"
- Zach de la Rocha
If you're eventually going to install all of the autoloaded methods anyways, it is better to install all of them up front when you load your module (by assigning to the typeglob if need be) rather than lazily installing them later (throwing away the method cache every time you do it).
Furthermore using AUTOLOAD does not play well with UNIVERSAL::can or multiple inheritance.