First thing to note with this DVD is that it is in no way authorised or done with the permission of the Rihanna Estate. This is important because it means there is minimal footage or interviews with Rihanna herself. None of her music is on the DVD, no live footage, barely any interviews.
It's VERY cheaply made, using stock footage and playing the same few interview snippets from Rihanna to pad out her story. The facts themselves of her story aren't even very accurate - at one point a friend of Rihanna's from her childhood is mistaken to be her sister, and they also talk about Chris Brown appearing on a remix of the song "Umbrella" which again, never happened.
There's a few saving graces in here, some quite interesting interviews with music producers who have worked with Rihanna like Rodney Jerkins and The Dream, but the majority of the people on the documentary are music critics and showbusiness executives who have very little insight into Rihanna other than statistics and hearsay.
I wouldn't recommend the DVD to be honest. It's not well put together, has zero imput from Rihanna, and the price itself is way too high to justify it.
Avoid it and look up interviews with the girl herself on Youtube, that way you don't have to waste any money.