I enjoyed the manga up till a certain point, but after that it just didn't hold my interest as it did when it first started. I'm interested to see how the live-action movie will turn out - I hope it's just as good as the beginning/middle portion of the manga was.
I guess I'll put my reason in hidden spoiler territory. For the record, I read up to volume 8 in scanlations, so it might be old news or *huge spoiler* to whoever reads further.
When L is finally killed, I stuck with the manga but the interaction between Light and L was the best part for me. When other characters like L were introduced, it just wasn't the same. Maybe I'll pick it up again as it's released in English.