Collecting up a few remarks from earlier, I found the HTF600 to be quite capable...for $30. I feel it could be compared, with obvious faults, to headphones reaching up to the $80-$100 range, with more expensive competitors gradually gaining advantage until the HTF600 could no longer credibly compete. My own SRH440 performs comfortably better for the $99 I paid (they're usually $10 cheaper now), serving as a useful cap on expectations.
Similarly, I thought the M50's technical capability merits anything up to around $150, though the upper end of that range is a bit optimistic these days, with a greater selection of closed circumaurals than when the M50 was first introduced.
In neither case would I say these are giant killers, though in both cases I have the benefit of reference and bit of experience. Hype comes when both of these things are lacking, as has been discussed above. Everything has its place, which only becomes clear in context.
Unfortunately, that context is often lost in appreciation threads because, by nature, the subject is going to be the headphone being appreciated. And, also by nature, appreciation implies positive impressions. Such threads will contain a disproportionate number of people who really enjoy the product, and some even who have a personal interest in its success. Taken out of context, every headphone with an appreciation thread will be the best thing ever.
The two things that help clarify a headphone's merit, IMO, are objective comparisons with similarly-performing products, and time. The first of these is easy enough to prepare; the other can't be controlled by anybody. The M50, despite being ridiculously overrated at one point, is still recommended and still holds up years later. Will we be able to say the same about the SE-A1000 years from now? We can't know until the time comes.