Yep, that's the one I'm using, not the 4K screen model tho, it boots to a black screen, and in my opinion, isn't worth the hit on performance/battery. Touchscreen doesn't work and may not ever, but it runs Ubuntu 16.04 really well, touch included. Just ordered a 1TB SSD for it and I'll do an OS X install write up after I put the SSD in.
Have you started a thread for the Dell XPS 12 9250 yet? How are you booting? USB-C Adapter?