If you were/are an Elton John fan, you will like this movie (except for a couple of sex scenes and language) As for me, it was kinda weird, but good (again, except the sex scenes, language didn't bother me much). It's basically a musical built around his music, covering a period of about twenty years. The music isn't chronological, but the events of his life are. What I didn't know was that he had a serious drug habit (like who didn't in the 70's) and he attempted suicide.
If anyone saw Bohemian Rapsody (re: Freddie Mercury) there have been some comparisons made, the major one being that RM didn't downplay Elton's sexuality, BHR did downplay it (Freddie's) to a degree. I liked both movies, each for their own merits.