Infinity is an interesting concept, but it's not an easy subject for a documentary. If you get some stuffy scientists to talk for 80 minutes straight, you get a lecture, not a film. And so it was smart to provide accompanying animations that have worth and appeal on their own, rather than a purely illustrative function. That's what made this doc stand out for me.
Part of the info here was little more than a brush-up of my student days, but the different analogies were pretty apt and no doubt useful for people who are new to some of the concepts presented. As long as you don't expect to walk away with more answers than questions, you should be good watching this documentary.
The main takeaway is that our brains are simply not equipped to deal with large numbers, let alone infinity. It's pretty cool to see how maths has evolved from a field that describes what we can see to something that describes things beyond what we can see, leaving us to believe in one of the abstract constructs man has created. Oh, and the animations really are fun and pretty too. Good doc.