I carry an XD9 (same size as the 40) in Texas. During the summer I wear shorts and a t-shirt. During the winter, I wear jeans and a t-shirt. It's concealable. I do wear it inside the waistband. OWB is too bulky. Also, I have to say that IWB, it would probably be easier to conceal the 4 inch XD rather than the subcompact that I have. The grip likes to angle out because it is heavy.
I'm saving my dollars for a Springfield EMP to replace my XD, but I can tell you that the XD is very concealable.
I'm saving my dollars for a Springfield EMP to replace my XD, but I can tell you that the XD is very concealable.