Starscream was always my favorite. Was upset he got killed in the animated movie in 1986 but oh well.
I do think they captured more of the essance of him in ROTF and he defiantely was afraid of Megatron. I mean he did see the writing on the wall and took a step back since the Fallen decreed Megatron's resurrection and the fact that almost all the decepticons were working towards the Fallen's goal. I know I would not try to take over during all that, would wait till a better time.
I did love it when even after Megatron blamed Starscream for all his own failures when he got the snot beaten out of him, an half his face blown off, who does Megatron yell for help from....STARSCREAM.