One aspect has glaringly stood out to me over the years reading DAP reviews, when you're spending mid to upper prices for a player hardly anyone has exclaimed something like: 'Wow straight out of the box this player is so much better than my current one, the difference is night and day.' Which I would expect especially from a player that costs about the same as a used car.
The differences are usually subtle, and often much A-B'ing is done to pin point the sonic differences. Often it's the faster processor, memory size, and UI that makes a player worth buying.
Whenever I've spent around $1200+, or intended to, I'm brought back down to earth quickly: 'this' player is good but so is mine that cost a third less. Maybe I expect too much and don't appreciate, or can readily hear the (slight) differences that many consider are worth upgrading for. For me battery life is the new benchmark whether I upgrade or not as I'm generally happy with how most modern players sound.