One of the things I like so much about TNU is the way it conceptually is similar to a lot of the things I like mechanically about Blades in the Dark, but with a setting/premise that is a lot more exciting to me.A huge part of what is grabbing me is actually the mechanics for interacting with society when you aren't on adventures. This is a big part of what I love about Blades in the Dark, is having actual systems to show how the PCs adventures and off time affect the rest of the world. Also, the nightmare design system looks very interesting and provides awesome tools for generating adventures without too much of a brain tax.
It certainly helps that the book is very well laid out, and has an overall clean and easy to read appearance, but still has plenty of art and graphics. This has always been a big deal to me. It is just plain a pleasure to read.