For concealment with a suit or sport coat, I quite like the side pocket holster. Obviously not suitable for a full-size service sidearm, but the quarters of your jacket permit you to carry something at least fairly effective with excellent comfort and good concealment.
I have always found IWB carry fairly uncomfortable with any kind of serious sidearm--and it makes you look as if you have gained 20 pounds. I know a lot of very competent people favor it, but I don't like it.
I have never had any use for Small of Back carry. How do you manage when you sit down? And if you fall on your back, you are risking a serious spinal injury.