Yes. On Bumblebee the police light on his roof activates the transformation. It's a spring loaded so pressing releases the clip and he pops open and then you manually position the feet and arms. You have to manually transform it back to vehicle mode.
The Bumblebee IMO looks really good. It has the feel of a classic Bumblebee toy, small simple to transform. It's arms are weak though, no real forearms. If I was only getting one toy each of each character the activator one would be the one I'd get for Bumblebee.