Can it beat the voice of John DiMaggio? But, meh. We have our favorites. But I think Sideways wins in design (All spiky and whatnot), voice in a video game, toy (You have to admit, the first Sideswipe was kinda hard to pose), and weapons. (Saw and badass sniper rifle) I must admit Sideswipe has an interesting alt-mode, a decent design, and I admit, awesome wepons. Now I kinda want to see a Deadliest Warrior fight between Sideways and Sideswipe....
"You're so weak!" -Forest Battle. Love how Prime just grasps at the giant claw coming through his chest and is then blown to bits. "Give me your face." -The former part was unnecessary, but the latter? Punching through a con's chest, grabbing his spark, and crushing it? Hot damn. "I rise, you fall" indeed. "I hereby discharge you from duty." -Solidified Sentinel's badassery and broke my heart all at the same time.
I feel like just choosing one is doing a disservice to the other insanely awesome ones, because most of the non-fodder character kills are fantastic. Despite that I'll single out Optimus taking out The Fallen. Using his own spear against him, ripping his face out, impaling him from behind and crushing his spark with his bare hand in front of his decimated face...just brutal. And the "Give me your face!" just adds to it.