I've done both. Built my own gaming PCs from the ground up by myself and purchased Apple products. My work laptop is a fully loaded Core i7 Macbook Pro with 8GB of RAM. My home PC is a 2007 Mac Pro. My HTPC is a custom built solution by me. And of course, I've purchased various off-the-shelf PCs, too.
Best way to explain it is the difference between buying a Subaru WRX STi versus purchasing an Audi S4, which is double the price. Both will get you great performance and the STi is probably even better. But combine the design, style, build materials and, yes, badge matters, and you got two different products.
Are there merits to purchasing both? Yeah, I think so. The inclusion of Mac OSX is worth it alone, in my opinion. At the end of the day though, it's your friends money. If he can afford it, he can afford it.