I pretty much argue for servo, too, but this is not because it is always the best solution, or even the best solution for this particular project, but because once you've gotten "over the hump" in software control, it adds a whole new tool to your prop-making.
Yes -- for opening a visor a gear motor and a couple of limit switches will work quite well. In a way is even safer; you won't crash the prop if you have a software problem. (Otherwise known as micro snap action lever switches...a tiny switch with a metal feeler that will cut the power when the motor reaches the point where it should stop).
And you can get very tricky with those thing; in the industrial world, there are controllers that ramp them up to full speed (instead of jerking into motion), go to several different positions on command, etc.
But...you can also do stuff like this in software. It seems like using dynamite to fish; to put a whole micro-computer in just to run a motor. But the thing is, once you have that micro, you can ask it to handle a bunch of other things besides. Control the lighting, for instance. And once again; in the battery-and-switch world, you click a switch and the lights are on. Period. In software (or in more complex analog circuitry!) you merely tap a button and the lights fade up. A second tap, and they fade down.
I'm doing a simple raygun right now, but I'm putting a micro in it; the micro will play back the sound effect, bring the LED to full intensity, hold it there for a moment, then fade it down; thus a complete "shot" takes place each time the trigger is touched. And by adding a potentiometer, I also have the ability to select other sounds/lighting, including a pulsating continuous beam mode.
It is a bit to grasp. Even the really, really friendly Arduino platform can take you a long weekend to grok (it took me longer!) But I think it is a good skill to be thinking about adding for certain kinds of prop work.
