So, I watched through "Power of the Primes" today, because I am an idiot. I didn't know it was part of a trilogy, specifically the last part. I'll admit to having never seen G1 Transformers, my first exposure to the series was from Beast Wars, and then Robots in Disguise. Still enjoyed it, I don't really think this G1 Megatron is as good as the Beast Wars version, but he is a solid second place.
To be honest, I only watched it because I heard Optimus Primal was in it, but they did him dirty. He doesn't transform, he's got a new voice actor and has no personality. I mean, I get why he was only added because of a popularity poll, or so I've heard. But they should have at least brought his original VA back...