CD is useful in some cases and is used by Kzin pilots. It is the first ship with B-racks and thus good for assaults.
The CL and CS are useless, period.
The CA is never flown either, but that pretty much goes for everyones CA, same with the FF. Dunno if they would fins usage with an OOB scheme, they might but I don't know as I tend to avoid servers with any major OOB restrictions other than BCH and up.