I travel the Ernakulam/Cochin-Bangalore route atleast once a month. My first ride on the KSRTC was my worst bus ride in terms of punctuality... the bus departed 1 hour 45 minutes late. Buses have been more or less on time since then, and I have been a regular on KSRTC. The ride quality on Airavath is excellent compared to any other bus, at a much lower cost.
Also, service quality is high here as they provide a blanket and even a bottle of drinking water. They are the only bus service where I have noticed a tag system for luggage in the rack. However, this is not enforced uniformly. Drivers look smart and professional in their crisp white uniforms. Bus interiors are clean and well maintained, though that might be because the buses are fairly new.
Wish the private lines would take a hint from the Government, for once. I CANNOT rate the "Knowledge of Tour Guides" as this has never been used.