You can get models with bigger lenses for more $, but they are less pocket-sized. Their performance is undoubtedly better in low light conditions, but I’ve found that mine functions fine on cloudy days and indoor meets. More than 240 FPS is really too slow anyway for every application that I use, but mine goes up to 400 FPS and finally 1000 FPS. You lose tons of resolution and still need super bright conditions at 1000 FPS, and realistically it’s only good for the ubiquitous drops of milk or needle-popping-a-water-balloon type stuff, not necessary for high quality video analysis.
Check out youtube vids of Casio Exilim to get an idea of what you can do. I’m personally sold on it.