Saw one in one of yesterday's games, not sure if it was Palace or Hull that did it, or for that matter if it was intentional...but they just played a ball along the ground into the area, completely caught out the defenders and allowed them to get a shot in. Whatever corners you do, you have to mix it up a bit.
Charlton did one first half where Steele had to make a good save , no variety in our corners and last goal I remember from a corner was Danny rose last season
I prefer them too but if you have a quality corner taker I would let them take from both sides. It's all about the delivery (Gok Wan came to mind then).