I have to say that I really dislike both Boy I Am and Transgeneration. Okay, I'll be honest, I really loathed both of them and found them a trial to get through. I'm glad I watched the first on YouTube (so I didn't waste money on it), and I guess the second was worth buying--it was bargain priced for about as much as it would have cost to rent it one disc at a time, and I couldn't find a copy in town. But now I want to get rid of it.
A friend of mine recommends You Don't Know Dick, but I've never seen it and don't know if you can get it through, say, Netflix. It's about FTMs--several different guys. I don't feel inspired to see such documentaries anymore, or I would try to track it down--I do know that I've never seen it on Amazon. Last time I talked to this friend, I think he said it had never been released on VHS or DVD. Also, it's been around for quite some time, so it might be dated.
I think somebody here recommended Transparent, but that's about FTMs who have kids--I think some of them even after transition. I don't think that's what you want, is it?