I have the C250, its not bad, and the videos I made with it are terrible, and they're not really showing its true potential. Obv not as good as some other options, but good for £15 (thats what I got the C250 for.)
Here is a bad lightsaber duel with it. Don't watch the animation etc, watch the quality. (And don't watch my other uploaded film... that is the camera at its worst, it was my first brickfilm
)
But yeah, I recommend it as a cheaper and less 'good' option to the other expensive thing.
(I know you're talking about the C300, but the C250 is simply just the earleir version.)