Apart from medicals, I've had very little interaction with CASA (fortunately). However, although the organisation's management is roundly maligned and probably deservedly so for its culture, legalistic attitude and heavy handedness, I will say that our local CASA guy who runs the regular safety lectures - my only other direct contact with CASA - is excellent. Very helpful and well informed, and I'm sure there are many others in the organisation like him who have a real interest in aviation and are doing a good job.