I saw the new movie version. I thought it was very good. I thought that the Harry Potter kid did well in the lead role. I thought beforehand that I might not be able to take him seriously in a grown up role (like Leonardo DiCaprio). But he did a good job.
I've seen the stage play and the British TV movie from about 20 years ago. I haven't read the book though, so I don't know which is closer to the source material. The TV movie is, in my humble opinion, much scarier than the new version (especially in one specific part). But I thought that the new movie was very good, nonetheless.
Also, it was actually a Hammer film. When I was watching it, I kept imagining what it would have been like if was made 50 years ago....