I personally think Mac's suck for GFX, only thing good is the clarity. But it's very unergonomic. And the reason I think it's so "quick" is because there's almost nothing on it. Macs are so linear it's scary. You can't do shit to them, and you have to only use what Mac gives you. There's like zero customization.
And trust me, your Mac will slow down as it ages. And there's nothing like a lagging Mac.
Well for the customization aspect of it, like I said, there are sooo many widgets and apps you can get for it. Seriously for whatever you need. And I don't buy that it gets slower as it ages because almost everyone that I know, that has one, still have their Macs and they were extremely quick. And they've had it for a while.