I imagine this would have been much better received had it been simply called something else, with different names for all the recognizable characters. Because this barely resembles the "Robin Hood" we've all come to know over the years. Not that that's necessarily a bad thing. This is like the Batman Begins of the Robin Hood story, if we didn't see Batman until like the last five minutes of the movie. Hopefully there's a sequel, that would be more comparable to The Dark Knight. It definitely set the stage for one.
The production values were fantastic, the photography was great, and the acting was as good as you'd imagine. Everything made sense and there really weren't any plot holes worth noting. Overall it's a very well made film as you'd come to expect from Ridley Scott, but it was SLOOOOOOOW. Which is normally not a problem for me, but it definitely seemed like they could have trimmed a good 30 minutes or so off of it, especially considering it's just the story of how Robin Hood came to be. I don't know how historically accurate it was, so take that for what you will.
Overall I'd recommend it, just keep in mind that most of the things we associate with Robin Hood are absent. If you don't mind that, or its length, it's about as well-crafted as films come.