What a coincidence - I watched this last night.
I did enjoy it; I think DiCaprio catches unwarranted shit for his acting ability. He's been great in the last two movies I've seen him in (this and Gangs of New York). He just got tagged with the "pretty boy" label because of Titanic, and it's not deserved.
I agree that it was a little long, but it never really felt boring to me. It's too bad they didn't find time to delve into when he really went crazy, but that would have made the movie like 4 hours long. I still want to see Hughes wearing kleenex boxes as shoes and not cutting his fingernails for months.
I'll steal from you and give it an 8/10. Some parts could have been left out, and Gwen Stefani has no business pretending to act. The cinematography rocked (especially during the Hell's Angels filming) and the acting was very solid all around.