I switched all of my non-server operations over to Macs and will never turn back. I'm pretty convinced that anyone that feels like bashing them either can't afford them or just never gave them a fair shot - and that's fine.
If you need Windows, get parallels which sets up a virtual machine for you and install Windows on the virtual machine. No big deal, but that's if you really need Windows at all. Most software developers who are at all serious create applications that are OSX native at this point. That's a growing trend since Apple made the switch to Intel processors back in what, 2007?
Anyways, unless you are running link building software that is incredibly hardware intensive from home (which is stupid since those programs should be on a VPS/Dedi with much better connectivity anyways), then Mac's are superior for virtually every other marketing related task.
The App Store is a really nice benefit for adding any additional functionality that you might want or need.
The retina display really reduces eye strain and fatigue if you actually work long hours and don't treat this business as more of a hobby.
I find the keyboard ergonomics superior on both my Macbook Pro Retina and the wireless bluetooth keyboard that comes with the iMac. In fact, that desktop keyboard is really quite nice.
If you want to buy a single terminal and have both a laptop and a desktop, consider a dock like these:
http://hengedocks.com/pages/vertical-macbook-pro-retina
Additionally and what the Windows crowd has conveniently forgot to mention, or should I say like to avoid, is that since OSX is essentially a forked version of linux with a GUI, many linux commands (or slight alterations of) work directly from the terminal in OSX meaning that you maintain a degree of continuity between your workstation and server experiences. This becomes more important as you begin to have to manipulate large text files, something Windows and DOS commands were never really equipped to do outside of the copy /B command at best.
People have brought up gaming, and that has nothing to do with marketing - but Steam is available for OSX and there is a large library of games available that run just fine.
After Microsoft's disastrous Windows 8 (which is what made me run from my i7 Vaio into the arms of a Mac) do you really want to put a thousand dollar+ investment in the hopes that they get Windows 10 right?
Additionally, porn looks great on a Retina display
Suggestions:
-Make sure you order your Mac product exactly how you want it directly from the manufacturer.
-If you get a desktop, the 5k Retina isn't really worth it, yet.
-If you plan on using Parallels and Windows, get at least 8GB of ram, 12-16GB preferred.
-The SSD in the Retina models is worth every penny over the platter drive in the non-retina models.
Last but not least, if you can't afford it, don't get it.
Look, using a Windows machine isn't the end of the world. I still crack open mine every now and then and it's not a life-ending event. They will work just fine for what you will probably need to do.
Owning a Mac comes down to the user experience. Some people get that, others don't. Some people want to look at things on a processor-to-processor level and don't understand that you don't really use the processor - you use the computer as a whole - and there's a factor at play in all of that which isn't so easily quantified.
If you are use to drinking Jack Daniels then you will think that's perfectly fine and life will go on without any drawbacks. Once you taste Black Maple Hill 21 Cask 7 Bourbon however, you might think that maybe you'd rather drink that instead...