Let me comment to start with that this is perhaps not the best place to ask this question. Also, it is rather a leading question which, predictably, has elicited the responses it was intended to. I'll answer it from the perspective of someone who owns two Macs, three PCs, and a couple of Raspberry Pis. I run OS X, Windows (various versions), Linux, and FreeBSD.
I think there are two broad categories of Mac users. (1) Those who just want an easy to use general-purpose computer. (2) Developers.
Macs can appeal to the first category because they provide an easy-to-use operating system and are part of an extremely well-integrated ecosystem.
(i) The App Store provides a central repository of software, both free and paid for, that is guaranteed to work on your computer. It is clear that Microsoft are now trying to emulate this with the Windows Store - so far something of a failure.
(ii) Users don't need to bother with device drivers and the like. Because the infrastructure is so closely controlled the software just works with the hardware supplied. True it is a much more limited range of hardware, but the people we are talking about here are not typical Tom's users who worry about how best to apply thermal compound. They just want a computer that works; they are not going to be spending $500 on the latest graphics card.
(iii) Macs don't come with a whole bunch of bloatware and trial software as Windows PCs often do. They are already supplied with the applications that most people want to use - web browser, email, word processor, spreadsheet, presentation software, media centre, etc.
(iv) Macs are ideally paired with iPhones, iPads, and now iWatches. All these are undeniably, popular products.
(v) Probably a good way to determine those aspects of the Mac that users like is to look at those that Windows is now copying: centralized software store, free upgrades to the operating system, multiple desktops, etc. Of course, most of these are not Apple innovations; it's just that they have latched on to them and copied them quicker than Microsoft have.
Developers like the Mac because of the wealth of software it provides.
(i) Being UNIX, just about any UNIX software can be ported to OS X (or already has been). This includes a vast array of programming tools and languages that are not available for Windows.
(ii) If you want to develop Mac specific (or iOS) software you need a Mac. Period. You might think the same could be said for Windows, but it is not quite the same situation. If necessary it is easy, and supported, to run Windows on a Mac, either natively or in a VM. The same is not true the other way round. Anyone who follows this forum will be aware of hackintoshes - they will also be aware that these are unsupported and, from the number of questions we see about them, not straightforward.
Where Macs are totally unsuitable (IMO) are for games playing and for use in business situations. Since Apple gave up on server operating systems they just don't provide the structure to support business networking that Microsoft does. For corporate use Microsoft is king.
I haven't mentioned Linux here; I don't think I need to. Linux users will look at this thread and just say WTF?
In the end this is not a question that is going to get a satisfactory answer here. The sort of people who use Macs are fairly unlikely to visit Tom's (just look at the space dedicated to PC hardware and software as opposed to the two forums dedicated to Macs - and those are mostly filled with questions about running OS X on a PC!). And sometimes it is a decision based on totally irrational reasons. For example, some people just don't like Apple; some people just don't like Microsoft; some people just don't like either of them.
Typed on my Linux PC.