Just back from watching this.
I guess you can't really show a life in two and a half hours, but I feel like it was a fairly superficial look at her life. The film Elvis, imo, did a better job of getting to the heart of the person.
I feel like they used the film more to showcase the talent that she had, rather than the demons that led to her drug use - they were there, don't get me wrong, but in a 'this happened and this happened' way, not in a 'this is how the things going on in her life affected her' kind of way.
I think the casting was really good, and it was interesting to see how the person she was portrayed as being was different to the woman she was. But it felt a little too 'nice' - like it was too soon to really explore the darker side of her life in any depth.
Worth a watch though, even if you aren't a fan (I'm not), but would maybe give it 6/10.