As far as I can tell, the Mooncup is the British version of the Diva, which is the silicone version of the Keeper, which is latex/rubber.
I use mine if I know I can be home in time to take care of it, and it works well. I don't use it on my monster days because the poor thing would be flooded out within an hour--if that long. But that's just me and lovely perimenopause issues. Two days ugly and the rest light, I can live with.