Every since I got my M&P 9mm FS I have fallen in love with this line of guns and wanted to get a vtac model but now I have a chance to either get a 40 or 9mm vtac M&P for same price. Two sides I am fighting with is I already have a 9mm so I wouldnt have to buy a second caliber of ammo but if I got with the 40 I could always put a 9mm barrel in it correct? Is there anything else that I should be thinking of, the 40 caliber ammo isnt that much more expensive in my opinion. I will prob keep the 9mm with truglo sights as my ccw unless the vtac is that much nicer. Are there any pros and cons of choosing one over the other?