I'm a newbie, but I would definitely buy one of the patches. I think that a patch would make the uniform look more "realistic", but I wouldn't feel right wearing a real unit's patch.
I remember when I played similar games years ago, and was part of the first unit in our group. Of course, being #1, the official patch was the "Big Red One". Even as a teenager I thought it was somehow wrong to wear a patch that so many people had worked hard to earn and worn to their death - it seemed almost like an insult to them to wear the same thing while just running through the woods shooting little plastic bullets at my friends.
So, yes, I would like to have an official "Airsfot Arizona" patch that I could wear with pride - the alternative for me is an empty shoulder.