Anubis is fine even without Dark sub-Eidolons, she's at 80% without any. Still way better than any alternative.
The 50% ones are awful because they're only decent when you can use a full set of sub-Eidolons without losing much Atk. Which is pretty much impossible.
EDIT:
This doesn't hold true for fluffy and Anubis as far as I know. A MLB Anubis is still 80% base, but gains 8% per sub-Eidolon instead.
The 5% increase in base happens for the 120% Eidolons though.