I would think of switching because I am disappointed at Apple and for some other reasons. Here I go:
1. Price. Yes, Macs are expensive. But I am in Brazil, and that makes things even more expensive. The government charges a huge amount of taxes, about 100% over the final price of a Mac. That means that, under normal circumstances, I would pay twice for a Mac than I would pay in the US. In the recent days, due to the corruption scandals everybody should have heard of at this point, the exchange rate raised about 50%. So, if I want to buy a Mac now, I would pay about 3x what I would have paid in the US under normal circumstances. And that is a lot of money. That apply to all computers, but there are cheaper alternatives. Yes, they may be inferior, but what so? Would you pay US$ 3,000 for a low-end MacBook Air? Or US$ 6,000 for a 15-inch retina MacBook Pro? Well, I won't. It's not Apple's fault, my government screwed up here.
2. Apple is paying too much attention to phones and watches and now the rumor is... cars. As a result of that, OS X may be fine and all, but that is pretty much it. Apple leaves to third parties to produce software. Guess what? Software companies will make software for Windows, which represent 90% of the computer market, and, as far as I know, has a better (or easier) programming environment. I don't want to pay more to have inferior software, and I am not talking about the operating system here, but of everything else. Apple is not spending its billion dollars in developing software for Mac, apart from the OS. If Apple is not interested in computers, why should I be interested in Apple's computers?
3. Apple's simple approach. If I pay a lot of money for my computer, I want it to do everything, and to be able to do complex stuff. Apple's approach, however, is simplicity. The new MacBook is a result of that. Very fine computer, but just one port and a slow processor. Look at Apple's software as well. iWork is a joke, and lacks so many features. I would have to rely on Microsoft to make a decent office suite for the Mac. But guess what Microsoft has its own operating system, and it has 10x the market share of OS X; it's no surprise that the office Microsoft produces is far better on its own operating system than on the operating system of its competitors. And it's fine for Apple.
So, why should I consider paying a lot of money triple what an US citizen would pay for a laptop that is beautiful but that is also underpowered and has only one port, and runs third party software that cannot hold a candle to software that runs in a laptop that costs half the price and is, in addition to that, more powerful, even though it is not as beautiful?