What got my interest was the 8,750TBW that Intel claims for the Optane SSD 900P. That should outlive me. The X299 offers PCIe 3.0 across 3 x16 channels, so no limits on devices that I plan to use. So, I already have Titan Vs, but I cannot bring myself to use them to play games, thus the XPs. The whole reason I am even considering an update is working with the higher resolution textures with Maya, Mudbox, Motionbuilder, Photoshop, Audition, FMOD, and a browser for listening to podcasts or streaming videos while I work brings about lag pretty bad. I plan on using Optane with a WD Gold 12TB HDD, but I have no idea if that is a good matchup, or not. The reason I mentioned the apps is because I know I will need a huge amount of memory (Photoshop alone has been breaking the 32GB limit), and I am looking for a MB that will support at least 128GB of memory (preferably 256GB but that is rare indeed).
I may have to approach Puget about this one, but I do love building them myself.