Not dated where I live: I've never met even one! I prefer
Cassandra, though it is becoming fashionable to use the ancient Greek K spelling rather than the English C:
Kirke, for instance, where it does change the pronunciation.
Kassandra doesn't.
I don't like either version.
Cassie and
Sandra do not appeal to me at all, and
Cassandra is inconveniently long for daily use.
I think the mythological associations are the best things about it.