I have 2 Calypsos. They're not the Nikonos (they're the precursor), but they're functionally the same, so I feel like my opinion is relevant.
These are incredible cameras from a mechanical perspective, and are super fun to use in a their intended setting. They produce cool as hell, unique as hell images when used in the water. They're also super fun to take in the shower or out in a rain storm. They're not complicated or prone to breaking. They are somewhat limited in their capabilities just because there are no teles, portraits, or great macros made for them.
Overall I recommend, but only if you actually plan to use them in a water environment. Otherwise and old p&s will do fine.