If I had to choose between a night dive or a daytime dive, one dive only, in blue water of the Carribean, it would be the night dive. I have seen barracuda, octopus, squid and other wildlife that I would never have seen otherwise.
Also, night dive causes you to slow down, to not out swim your light. With the slower movements, you can concentrate and see more.
Any day diving beats a day on the surface, night or day. Once you get comfortable underwater, you will wish for gills.