Santro is a very good car in its segment in terms of comfort on long drive or driving in city but it has 2 disadvantages.
Its not fuel efficient as per my experience its giving 8 to 9 kmpl in petrol.
Its ac is good when car its running as far as cooling concern when u are stuck in jam or waiting at traffic light it stop cooling, only fan work but to horrible in summer in delhi where temp go very high.