This will be short, and to the point.
This movie is not for everyone, the fighting of war is NOT the major point of this film. Some people will find it slow, while others will find it beautifully paced. The acting is incredible, not over the top and fake, but very believable and moving. The story is captivating, the way it unfolds is mesmerizing, and it will be hard for you to take your eyes off of James Mcavoy, he's that good as Robbie Turner.
If period pieces and romance is something you're interested in, then this is a film for you, if not, then you probably won't enjoy it. For me though, it was easily one of THE best films of the year, and I still can't forget it, even though I saw it almost three months ago.