So you are not even going to give any reasons?
For example, you could say that the carbon fiber palm rest don't feel comfortable.
I would disagree that, but at least that would be a reasonable argument.
I will, but whether this will be reasonable to you or not, I don't know. I would ask you to refrain from calling me names, though, even indirectly. I don't consider you untasteful or ignorant, so please don't consider me unreasonable or a fanboy.
And let me tell you, you won't find any of them to be good reasons for you. That's ok. As I said, you have different tastes and sensibilities, and I respect them. Please respect mine.
Anyway:
First, I really prefer macOS to Windows. There are a million little things and a few big ones, so I won't go into that here. I use Windows 10 daily, btw, so I am well aware how it works and looks. macOS is the biggest reason, and I consider it to be a part of the laptop, just as a CPU or a keyboard.
While the trackpads have improved on PCs, and XPS doesn't have a terrible one, I find it way inferior to any MacBook, especially the ones with Force Touch. I consider the input devices to be just as important as internal specs. When I use a mouse, I use a Logitech MX Master - and if there was a better mouse, I'd buy that one too, no matter the cost. I also need a good trackpad on a laptop - and, frankly, the one on MBPs blow the one on XPS out of the water.
In a similar fashion, I prefer the Mac keyboards. In fact, I really like the new Magic Keyboards and I actually like the new MacBook ones. Can't wait to try the butterfly mechanism on the new MBPs. I don't really care about key travel, but I am somehow OCD to keys leaning left and right while I type (I keep trying to hit them in the middle for this reason) so I actually prefer the new keyboards.
I dislike the feel of the textured surface on the XPS. It feels cheap. Before you get emotional, a reminder: this is my opinion and I consider it a matter of personal taste. I know many people who think it looks and feels great - I'm not one of them.
This is the part where you'll consider me a hipster fanboy, or unreasonable: the overall looks. First of all, I think you can do the same professional work on an XPS as the one on a MacBook Pro. Functionally, they are all the same - at least for what I do. But since I actually love computers, and don't just look at them as tools, but as something I enjoy and love, I go beyond utilitarian reasons. So - here it goes - MacBook Pros are esthetically much more pleasing to me than any Dell. I consider the XPS to be ugly. Sorry.
Finally - and this will seem ******* crazy to you - the attention to detail. I love how Apple designs these inside-out. Take a look at any picture of MacBook internals and compare them to the one you attached here. Please - I'm not insane - this is not a factor based on which I choose what to buy. Instead it displays a level of commitment that I respect. So don't take this out of the context and say: "he buys them because they look better inside". I remember a quote from Jobs where he compared a Mac to a good piece of furniture, and talked about the back surface, the one that is turned against a wall - the one you don't see. He claimed that if you're trully a master craftsman, you'll want that part to be great as well. It will just bother you if it isn't, even if no one gets to see it. This really resonates with me. I respect this attitude, and I try (and often fail) to incorporate it in my work. So, when I work and look at my Mac, it's a constant reminder to make that extra effort. To make even the things people don't get to see - the best I can. When I look at an XPS, I see what you would call "rational reasoning" and what I would call "compromise". For me, a MacBook is a reminder to try and do my best work.
These are my reasons. I am willing to pay for them, with the money I earned. People buy expensive stuff for various reasons all the time. I buy expensive Macs. I love them. It's as much an emotional decision as it is a rational one. Rational side of it is: I prefer macOS, I use macOS apps and I really prefer the input devices (trackpad and keyboard). Emotional side of it is: I just love the attention to detail. I love the symmetry and simplicity of a device that is so powerful. And don't think I'm some attention craving hipster either - I don't want to be seen with it in a Starbucks, I use it at home and in my office. I love how Macs feel. I really don't like how XPS feels. When I look it from the side, it looks like a weird robot ice cream sandwich. It's surface texture looks faux and cheap. I dislike Windows. That's just it.
Again - are these reasons good enough for you? Obviously not. And it's fine. For me, nothing is even close to a Mac.