Apple's edge: fewer choices
Apple's edge: fewer choices interesting, according to the article not having to carry a price/performace comparison of hundreds of different components and there combinations inside your head has a monitary value. So long as your free time is worth something I guess the difference in the amount of time it takes to price up and compare all the bits that go into making you cheaper DIY machine, instead of going "I want the brushed metal one", should be taken as part of the cost.
So Apples lack of a large product range apparently has other advantages than making sure that they test all the possible combinations, something microsoft can never do (due to costs of hardware) and Linux distrobutions cannot do in a systematic way (being reliant on volunteers for bug submissions), and make it "Just Work".