True. Vader's power truly manifested itself when Palpatine told him of his role in Padme's death at the end of ROTS... even with that terrible "NOOOOOOOOOOOO!!!!!!" that followed.
But OMG, what about Vader taking on those Rebel Fleet troops? That was something that I think a lot of people have been looking forward to seeing for a long time, and it did not disappoint. Seeing him fight his way through Admiral Raddus's flagship as the Alderaan troopers were trying to get the Death Star plans away from him was one of the most thrilling moments of the film. Especially since that melee ended with the Tantive IV undocking from the Profundity (yeah, that's really the name of the ship), and jumping into hyperspace.
Another incredible moment that I took from the space battle? The Y-Wings making their ion torpedo run on the one Star Destroyer, essentially disabling that ship. And THEN when Admiral Raddus ordered the Hammerhead Corvette to ram to the disabled Star Destroyer into the other, eventually taking out the shield gate? WOW! This may have been the best space battle I've ever seen in a Star Wars movie.
I also have to hand it to Genevieve O'Reilly who reprised her Mon Mothma role. I think she did a great job. And it was good seeing Jimmy Smits back as an older Bail Organa, right down to him ordering Captain Antilles around.