A junk holster. One day you are going to try to draw your gun and the holster will come with it, or the holster is going to break off from the paddle. (Even if you disagree with me on those points, they are just lousy for concealment).

My first carry gun was a full size M&P. I recommend getting a quality IWB holster from a reputable manufacturer (not Fobus and not a paddle holster).
I would pick something on this list
Guide to Concealed Carry Holsters and Accessories | Active Response Training

I also found it easier to go one size up in pants and get a thicker belt designed for concealed carry.