I'm surprised no one has mentioned what is probably the most important consideration in carrying a 1911, namely the external safety.
I have a commander sized 1911 that I do not carry, simply because I have not developed the muscle memory that is a prerequisite to carrying a 1911 as a defensive weapon.
In another thread about the M&Ps, I recounted what happened to me in a defensive pistol class when I failed to disengage the external safety on my M&P9c - every time - before simply leaving it disengaged. However, we don't have the luxury of carrying a 1911 condition one with the safety disengaged.
It's a fact that our bodies naturally resort to gross motor skills under stress, so when I had to draw and fire in the least amount of time possible, I instinctively tried to pull the trigger first without disengaging the safety. Now, compound that element by putting yourself in a real combat situation when your adrenaline glands are pumping at full capacity, and you can see the potential for disaster.
I had the safety removed on the 9c not long after that experience.
My take on it is that unless I am committed to conditioning myself to instinctively click that safety off, I am inviting trouble and am better off carrying a DOA weapon. It's when I think I can do this without commitment to regular, consistent practice, that I am fooling myself and inviting disaster.
That is why I don't carry my 1911.