It's a good action movie, and tells the story well with a few new elements added in. It's not a great cinematic masterpiece, but it keeps you going and provides a plausible idea of how a character like Robin Hood may have developed.
I would have liked a little more depth in the Merry Men's characters, and I thought Russell Crowe sleepwalked through a couple scenes. Also, like many movies, the two lead characters fall deeply in love without much of a chance to even learn each other's names.
The Good: Patented Ridley Scott action sequences. Cate Blanchett every second she's on screen. Some good humor mixed in..
The Bad: Prince John was too much the stereotypical "Royal Brat" that suddnely gets to play King. The WWII landing craft that the French were using took me right out of the mythos for a minute.
I liked it, but as others have said, there was a lot missing. It's a good bridge movie between Phonix and the next, 2-part finale. You definitely need to know the characters and situations going in or it will make little sense.
This is the movie I wanted to see when T3 came out. It keeps you involved and of course has great action sequences. I especially liked the focus on the Marcus character and his conflicted nature, though I did want more background on him. There are minor bits that might have been better served if done differently. For example, Connor's female companion is the Kate character from T3, but her name is only mentioned in passing twice and if you don't know who she is, you'll think she's just "that woman he got pregnant". But like i said, not crucial to the film, just would have been nice. Go see it. You are the Resistance!.