I have checked-out Three Kingdoms and it looks scrumptious. After wanting a TW set in China since forever I feel ashamed I can't bring myself to pick it up after a lot of negative reviews. Still on my list when a good sale comes along. Have you tried it Martok? Or anybody else here?
I don't know what negative reviews you've seen (although obviously every game is going to have some), but TW3K has generally scored very well. I know the DLC's are a little more hit-and-miss, but the main game itself has received a high degree of praise.
I have played 3K a bit, yes, albeit not much, partially because it doesn't run the best on my potato of a computer. (Looking forward to upgrading later this year!) The fact that it runs as well as it does, however, is a testament to CA's optimization efforts; it almost runs better than Warhammer 2, though admittedly this is not an immense achievement.
My "TL;DR" impression of the game so far is favorable: It looks good, sounds good, the variety of factions/lords makes for a high degree of replayability, battles are solid (note: I've only played the "Records"/historical mode, so I can't comment on duels), and at least in the early game, the AI is not only competent, but it "feels" like another player in the world (just like yourself). It all combines together to contribute an excellent sense of immersion & atmosphere, one that's at least the equal of what is found Shogun 2 and Rome II.
The only reason I haven't played Three Kingdoms yet is I don't have any companion reading to go along with it. And I'm a little intimidated.
I can't really help you with the former, I'm afraid. My interest in Chinese ancient/medieval history was primarily sparked by reading Sun Tzu's
The Art of War, which ironically was written centuries before the Three Kingdoms period.
As for the latter, I certainly sympathize. TW3K admittedly can feel a bit overwhelming at times.
Whenever you do get around to playing it, one thing I would recommend is picking a southern faction for your first game or two, as it's generally a bit less...intense. In contrast, I (not knowing better at the time) played as Kong Rong my first few attempts. I only later discovered on Reddit that it's typically advised for new players to start in the south, as northern China in TW3K is -- and I quote -- "an absolute thunderdome".