(Spoiler Free)
Generally one of the best adaptations of Lovecraft's cosmic horror stories out there right now. I'm a bit of a purist, and the modernizations/deviations from the original story bothered me a little and didn't really add much in my opinion.
Know that the relatively minor deviations to the story don't ruin it, and felt like just attempts at making it more palatable to a general audience.
The main plot points are all there, and at its core it's still the same story.
They did a great job of capturing the imagery of the story, which was very much Lovecraft's strength. The cinematography is absolutely gorgeous in this film, and captures the terrifying imagery of the original as best as can be done in a movie.
To address reviews that say this movie steals too much from other horror movies: This is an adaptation of a story that is almost 100 years old now. Lovecraft was one of the most influential horror writers of the 20th Century, and horror movies have been borrowing ideas from him for most of that 100 years. Other criticisms I have seen can't be addressed without giving spoilers, but most of the criticism leveled at this movie comes from people not paying enough attention.
Would recommend for Lovecraft fans, and would highly recommend to horror fans who might not be as familiar of Lovecraft's work.