There have been several threads on here asking the same question: what is high-end? In fact, that seems to be the most contentious and common topic here. I dare to add my views, based on little experience but some introspection.
I dare to claim to know the difference between high-end and mere luxury--what they call luxury today, I mean. For starters, high-end means artisanal works of highest quality. I would say "handmade" instead of artisanal but there is an honest confusion between pure handmade, and the general meaning of handmade; the first means without an assembly line, the second only made with greater time and care. Someone told me that the Robert Persig "quality" formula was based on "quality = time". Time not only in how long the work was in production, but also in design, and also the training of the watchmakers and even the history of the brand, building on its pedigree. The more time, the more quality. High-end watches, therefore, at the simplest level, have more time put into them than other watches. This time, or quality, can be sensed, but the better our taste and judgement, the better we can do this; those without, are like a bystander who walked by when I was looking at a photograph of a Breguet La Tradition for sale, and asked why anyone would pay so much when a cell-phone can keep time as well. It is not that his judgement overall is bad, and it is probably better than mine, but he has not spent the time to examine the merchandise.
I started off cheap but as I looked and looked at each brand, I realized that the "high end" brands are so superior in artistic design, quality, workmanship, there is just no comparison with even regular "luxury" brands.
In person the quality of a high-end item can be sensed, though on camera they look more like toys. But in person they feel substantial, both precious jewelry and functional machine. They are really "jewelry for men", both elegant, delicate, and masculine.
My two favorites: Breguet & FP Journe. These and the other brands to me are like the Rolls Royce (or Ferrari) of watches. They are not mere watches, but works of art; jewelry, and priced accordingly.
To me, the test of high-end is a brand based on true quality first and marketing second, as opposed to non-high-end, (sometimes called "luxury") which is based on marketing first and quality second. In this, it is like the stereotypical used-car salesman, pushy because his vehicles are rusted-out-undercarriage lemons. Such a salesman must be pushy and a fast-talker since his products cannot sell themselves.
Another test to me is whether the work can be easily imitated. When I saw the dial of a FP Journe Chronometre Bleu, one of my thoughts was that it was unique, since I had never seen any dial of such a midnight blue color, not even the Rolex & Omega blue dials could compare. I would be surprised if any offshore factory could create the same; besides, to imitate would be a contradiction, as the imitation would cost near as much if it were a true replica, which would defeat the purpose of replicating it.
Branding is vulgar: True high-end products achieve recognition without branding; the design itself, without logos, allows us to identify it. Just like I can identify an Hermes tie, though there is no "H" logo, by the silk twill and the "whimsical" design patterns. For FP Journe, the second I saw it, even before I knew anything about movements or details, I could tell it was incredibly "French" in design. Take away the logo entirely, I can spot it at a distance.
I would also note that high-end products, be they clothing, automobiles, jewelry, watches, are (ironically) not wasteful but economical and environmental, as they are never thrown away, barring some unlikely trauma. Ferrari automobiles don't go "out of date" in style or performance; neither do Hermes scarves.
Visiting the Tourneau Time-Machine's top floor, and experiencing clumsy/aggressive salesmanship (Financing! 12 months no interest!!! Buy BUY BUY!) I had to walk away in disgust. This is because high-end watches are designed by and for those of a certain judgement; Toyota created Lexus to have not just a separate marque but separate dealerships, marketing, all designed for a different customer. The executives at Toyota know very well there are different levels of judgement as well as taste in the population, and design the buying experience accordingly. High-end is simply products designed for the group of customers that has the most refined judgement, and the means to act upon it. Relativistic counter-arguments, such as "it is high-end if it is high-end to you" are not based on fact, and frankly, if "snobbery" exists, it would exist more in those who think nobody could have better taste & judgement than themselves.