The acting by Daniel Day-Lewis is superb.

Rating: 7/10 (18 November 2011)

Before I began watching this film, I read through the IMDb trivia for "There Will Be Blood". It mentioned that Daniel Day-Lewis got inspiration for his role by listening to recordings of John Huston's voice. Well, it's pretty amazing, as his voice DID sound just like him--and it's a bit weird. His acting throughout the film is exceptional--and I can see why he earned an Oscar for this performance.
Despite this and despite this being a quality film, it's also an incredibly oppressive and dark film---and I am sure it will NOT appeal to everyone. The plot is just unrelentingly nasty and the final portion where the film appears to have a strongly anti-religious bent will alienate people. However, at the same time, it impressed many--and is currently a very highly rated film on IMDb.
Day-Lewis plays a misanthropic jerk--one of the cruelest and nastiest in film history. He makes Ebenezer Scrooge look like a pussycat--and late in the film it becomes apparent that he not only hates everyone and is evil but he's also a sociopathic killer. This ending appears to come from out of no where...and once again is bound to alienate more than a few people.
Overall, the film is a masterful performance by Day-Lewis and the film has many fine moments. I was also impressed that the latter portions of the film actually used real deaf folks using real sign language (this is not always the case in films)--and they were quite easy to understand if you know the language. Oddly, however, when I watched this movie on cable, it was NOT closed captioned!! I assume the DVD did have captions. Turnoffs would include pretty much the entire last 10 minutes of the movie. It just seemed too foul--too dark. And, I felt a bit cheated, as I'd spent so much time on the film and had enjoyed it up until then.