This documentary has everybody (except Frank Welker, who I understand was working too much to sit for an interview), from the names I mentioned above to Mark Hamill and Mel Blanc's son Noel, to a number of prominent directors like the wonderful Andrea Romano and casting people and voice agents. This level of access was almost certainly the result of DiMaggio's involvement, and gives the documentary a level of intimacy that could have been elusive if a this were a fan-made project created by outsiders. The result is not only a candid look at the life of a voice performer, from top to bottom, but also a celebration, where these extremely gifted performers are able to geek out about the talents of their peers and the legends who inspired them to get into the business in the first place.
Look, this isn't a hard-hitting documentary that's going to give you a gut-wrenching insight into the human condition, but for what it is and what it sets out to do, I'd be hard-pressed to show you a more enjoyable ninety minutes of talking heads.
The Math
Baseline Assessment: 6/10
Bonuses: +1 for the level of access the filmmakers got; +1 for a thorough picture of the whole donut, as it were, from first gig to interacting with convention fans after a huge hit
Penalties: None
Nerd Coefficient: 8/10, which on almost any other site would be even higher.