Yeah, I've heard After Effects is even harder to learn than Final Cut. I remember downloading the trial a few years back, and there were just so many menus and options and panels... it was overwhelming, to say the least.
@ elbekko: Okay then, name one thing Macs can't do that Windows can (beyond the obvious, such as gaming).
@ Jessii: How is your client having a hard time getting used to a Mac? I used to use Windows, too. However, a few years back, I switched to Macs. It took me roughly 3 hours to settle into Mac OS X, and I was working as usual within a day or so. Also, the model you were probably using was a Power Mac (newer version, same looks is called the Mac Pro). It looks heavy, but it's all aluminum, so it's actually pretty light.