I have a lot of friends who love the food there, but primarily all non vegetarians... vegetarians dont get anything great and probably have a tough time having a decent meal... nothing very authentic also...
If you are the kinds who miss homemade Mallu food and would settle for something quite below expectations, Kaayal is fine. The menu is good, they have a lot to offer, is even good for a lot of people who like Kerala food. But if you've eaten Kerala food from Kerala, Kaayal pales to nonexistence in comparison.
Even when all the curries, thoran, sambar, fish, chicken, beef and whatever else you've ordered is good, the way the boiled rice tastes is the bizarrest thing (I've stopped eating rice there and stick to idiappam/kappa, coz the rice has a disgusting taste and smell).
But the fish fry there is one of the best available in Bangalore. Doesn't have the fishy smell and is very well fried. The beef is not bad, fish curry is sometimes delightful and sometimes disappointing. Depends how lucky you are. The idiappam and chicken curry are good. The one thing that's always good and better than anywhere else in Kaayal is the butter milk.
Breakfast is easily the best thing here, lunch & dinner average. Not too expensive, goes very easy on the wallet.