I saw Red Cliff Part 1 and 2 a while back, can't find the review I wrote back when I watched it, so I'll do my best from memory. Also not sure if it's being released in America as 1 movie, or in it's 2 parts, so the American release may vary from my review.
As I recall the battles were definitely some of the best I've seen. Lots of strategy involved, and the cinematography keeps you well aware of the overall structure of the battle. The actual person to person fight choreography is fairly simple but suitable for large war-fare style fighting. There's no flying around or anything, but some suspension of disbelief is required for generals who take out bunches of armed soldiers bare handed. There's a solid amount of blood, not a ton, but a realistic amount.
The plot as I recall was really simplistic. Not so bad it was annoying, but not terribly great either. Just kind of passable. There's often really long passages between the battles, which I was alright with, but may bore others.
Very worth seeing if your a fan of this kind of stuff, but nothing too great.