In short: Unless the notion of a paid mod offends you on principle, consider buying this if you're a fan of Warband.

It's very rough in places and extremely polished in others. It's important to remember the devs are Chinese, so don't even bother trying to create a character that's not Han or Xiongnu. The Western areas are very much unfinished, but that's kind of ok.
If you play as a Han, the experience is somewhere between a massive and complex mod and Viking Conquest. There are story campaign elements, but they're shorter and less linear and detailed than VC.

I have to admit the setting appeals to me greatly and contributes to my enjoyment of the game. It's not the common Three Kingdoms era, but some time before that. You'll venture more into the western parts and encounter wildly different cultures of the steppes, even the Yuezhi who later conquer much of northern India.

I'm well into my first proper playthrough, but it still feels like I've barely skimmed the surface. I found one single companion and just flipping through the manual (Oh yes, there's a manual! Read it.), I've not run into ANY of the many unique quests and hidden easter eggs.
You like easter eggs and hidden quests? Boy oh boy! One of the first things you probably notice is that your character can drown, but also staying under water trains you in holding your breath longer. (!!!) That's a hint for a unique hidden secret thing btw. (blew my mind really)

I'll update the review when I get further, but I felt I should recommend the game at this point, because I feel I've already gotten my money's worth.
The devs seem to update the game quite often, so hopefully more fixes and content injections are coming.