my thoughts on X:
It's a new business model for apple.. and a tiny bit of a sour taste. Basically they are releasing a new tier of iPhone, a Pro/premium tier. For a company who already occupied almost all of the oxygen at the premium tier, it sort of feels like they are introducing a "premium premium" tier now.
tech-wise, I have no question in my mind whatsoever that the X is a value at that price point. Apple's IPS for its CPU was already so far ahead of other manufacturers, its NVRAM is stupid fast, its camera is best in class, etc.
Still for many who were used to getting Apple's flagship product for $650, it's a bit of a sting. Going forward it looks like $650 will get you last year's flagship, and to stay at the top you are looking at $1000.
Is the X worth it? Probably. Does that mean many won't be able to afford it. Yeah. That stings for those who can't but used to be at the flagship level (and that may be me after X)
edit - biggest two reasons for upgrade for me.. (coming from 7). Screen size upgrade without the body size increase, and the Plus camera features in the 5" body. they aren't huge reasons.. but I figured I'd jump on this year, then go back to upgrading every other year (or more)