I would say it depends on one's usage. My daily driver is a late 2013 MBP 15" and the performance is more than enough for what I do (mostly sysadmin / light dev for work and Lightroom / Photoshop for my own time).
As other comments have pointed out, a comparably specced PC is not that much cheaper and would be much more of a hassle.
During those six and a half years I knew I could count on this machine and I never had any annoyances with it. If I had gotten a PC which was unlikely to last as long, I would have had to change it at least once, which means going through a period of not quite broken but not quite hassle-free either. And two PCs with the specs of my MBP would have cost more. I'm also OK with paying a premium to not have to deal with those issues (noise, screen sometimes not working, ports failing, keyboards dying, etc — all issues I've had with "pro-level" computers, mostly HP).
There's also the fact that at the time a similar PC was extremely rare (maybe the X1?). I'm talking about a computer with thunderbolt, high resolution display, the ability to run a 4K display at 60Hz, fast SSD. Granted, all those are much more common today.
I'll refer you to the other thread trending today about a blogger who upgraded from the Macbook Air I have to a new Macbook Pro and doesn't like it.
I also have Dell and HP equipment, and most of them have weird driver issues with the basic hardware after about 2 years. I don't want to live like that... I currently have an i7 Dell laptop that randomly disables the keyboard based on which WiFi network it's connected to. The other Dell I have spent its first two years of life re-installing the wrong SSD driver with every Windows update (when it crashed, I'd have to boot into safe mode and re-install the correct SSD driver that I kept on a thumb drive).
So, yeah: Dell is out. Looking at other brands, and desktops.
As other comments have pointed out, a comparably specced PC is not that much cheaper and would be much more of a hassle.
During those six and a half years I knew I could count on this machine and I never had any annoyances with it. If I had gotten a PC which was unlikely to last as long, I would have had to change it at least once, which means going through a period of not quite broken but not quite hassle-free either. And two PCs with the specs of my MBP would have cost more. I'm also OK with paying a premium to not have to deal with those issues (noise, screen sometimes not working, ports failing, keyboards dying, etc — all issues I've had with "pro-level" computers, mostly HP).
There's also the fact that at the time a similar PC was extremely rare (maybe the X1?). I'm talking about a computer with thunderbolt, high resolution display, the ability to run a 4K display at 60Hz, fast SSD. Granted, all those are much more common today.