Titan Xp is for people who want to blindly acquire the "best" they can and do nothing to it, or for serious OC tweakers who want to mod the card to get maximum performance (water cooling, shunt mods, etc.).
I actually bought a Titan Xp because I want the 1080 Ti FTW3 and it's not yet available.
They are not binned chips that are guaranteed to be better than other cards. The memory is the same lottery game you play with all other cards.
If you take a look at Overclock.net's Titan Xp thread, you'll see core and memory overclocks all over the place.
I got an okay overclocker in the Titan Xp, but it's noisy and gets incredibly hot. Frankly, I was a bit offended at the price premium I had to pay for something that really just isn't built nearly as well as EVGA, Gigabyte, or Asus versions of NVIDIA cards. Out of the box, it's a Founders Edition Titan Xp, and you have to spend extra time, money, and warranty invalidation if you want to bring it up to snuff.
I have no doubt that the Titan Xp is better than the 1080 Ti Founders Edition. Legitimately better than a 1080 Ti built by a good company? Heck no. I pulled the Titan Xp out last night and put my EVGA 1080 FTW2 back in and significantly preferred the gaming experience (noise, heat, stability, lack of crashing the drivers for no apparent reason).
The Titan Xp is being returned.
I have a Zotac AMP Extreme 1080 Ti on the way and plan to replace it with the EVGA FTW3 when it's out.