I have held the opinion for quite a while now that better one understands "classic" Perl OO the more one can understand just what Moose (and the rest) are doing for you. And depending upon circumstances and/or goals (such as the $work environment) it might not be feasible to take advantage of them. If that is the case, then a solid understanding of classic OO allows you to do pretty much the same thing but in the restricted environment.

My favorite tutorial by far has been the Animal Farm (Talk with the Animals) one, it is listed above but is no longer part of the core distro. :(