Good question - it is something I regularly wrestle with myself as I evaluate the various hardware and software options out there. In the end though, it always is a matter of tradeoffs based on your personal value system.
For the past few years, the most valuable property that I have tried to maximize when pitting multiple hardware offerings against each other is time. For other people it may be money, gaming performance, or other intrinsic values such as freedom.
For me, buying the latest Apple hardware as default has become the easiest way to maximize time: I do not need to perform exhaustive research across the market, the shopping experience is smooth, support is same day and local, the resale value is high and selling is easy, the hardware supports the tools I have built my current workflow around (a UNIX command line, emacs shortcuts system-wide, Xcode for iOS development, Photoshop, etc.), and configuration and backup is simple (iTunes, Migration Assistant, Time Machine, and iCloud for a limited scope of data).
Now obviously a lot of this is a result of vendor lock-in, which I try to remain vigilant about. How did I get fooled into being locked in?
It is simply a result of a string of great experiences early on in my dealings with the company. All companies provide varying levels of experience across their lineup of products and services. In my opinion, Apple manages to have more peaks in more fields that matter to me. The early positive experiences in areas that resonate deeply with me, built a great deal of respect and trust in the people who create things at Apple, earning them the spot as my default hardware
Regarding the Retina MacBook Pro product specifically: it is still "one of the best [computers] I have ever used" because it hits peaks in many right spots. The performance, portability, keyboard and trackpad, how it fits in my backpack and on my desk, design, ecosystem, and OS X are all positives for me. What I believe to be low points (Wi-Fi issues, video card performance in certain situations, Mission Control, the annoying MagSafe 2 adapter, iPhoto woes, etc.), are tradeoffs I am willing to make.
The "ghosting" is the one point I cannot concede. I work with pixels and color too much to let it slide. Thus far, Apple has offered me one replacement, with a free SSD update thrown in. I consider that great support, but poor quality control.
This is an interesting tradeoff because of how the two fields are closely related. Poor quality control necessitates good support. Whether that support is good enough (or the quality control poor enough) for me to continue leaving Apple's hardware as my default depends on whether they offer me another replacement, and whether that one is satisfactory.
Times change though. Open hardware and software is more important to me than ever. We must all be able to tune the properties of our hardware and software to our liking, without sacrificing the state of the art.