Well if the model he gave was the correct one the answer to your question should be obvious. One is a pistol one is a rifle. If you are gonna smart mouth newbs you should probably spend 30 seconds on google to avoid making a fool of yourself.
As to the OP, sorry bout your luck dealing with the issc. 99% of warranty issues today will suck but eventually things tend to get fixed. Have fun with the m&p while you are waiting.