SIG P220s have a reputation for being the most accurate DA/SA .45ACP pistol out of the box.

If you are going to get SAO, you may be better off with a 1911. Proper SAO carry is Condition one. Hammer back, safety on. The small safety control on the P220 may be slower for some folks to operate under stress than the 1911.

On the other hand, if you are transitioning from 1911 to SIG, you may prefer SAO for the familiarity.

I'll dissent a bit from submoa's good post.

I think the chances of getting a reliable P220 are close to 100%, while the chances of getting a truly reliable 1911 are rather less. I've only handled one P220SAO, but the safety seemed large enough to operate easily. Then again, I always used the stock (small) Colt safety back when I still carried a 1911, and had no issues with it in tens of thousands of rounds fired in practice, competition and formal training.

I would choose the SAO in a heartbeat over the standard TDA gun. I very strongly prefer guns with consistent triggers, and shoot them much better than crunchentickers. Have you had a chance to compare them side by side on the range?

Then again, probably only well-trained and well-practiced shooters have any business carrying a cocked and locked pistol. If your honest assessment of your own skills leads you to the TDA gun, go for it.

Either design will serve well for defense. Remember that gun selection is of very minor importance compared to mindset, marksmanship ability, gunhandling skill, and good tactics. Pick the gun you like better then move on to the more important stuff.

Clarification: Is the model you're considering SAO or DAO? It's possible it was a typo; the letters are next to each other on the keyboard after all.

In terms of SAO, I think I agree with submoa; if I want a 1911 I'll buy a 1911. Sig even makes a 1911-variant. Given the preferred carry mode the safety has got to be fast to disable, and Sig's isn't.

I would not buy a DAO unless there were no other choice. You want the single-action pull weight; if you walk into the range with a DAO, you'll walk out with a very sore trigger finger. Now I don't mean safe-action; a safe-action pull is comparable to a single action in weight, but longer. A DAO is 12-15 pounds every pull, and that wears on you, as well as hindering rapid fire and double-taps.

So, if you want a Sig, go with TDA.

Is the P220 available with the DAK trigger? If so, I'd get that in preference to the TDA gun. The DAK trigger is pretty light. No more sore fingers.

The P220 Carry is available with the DAK trigger (7 lbs.). I have the DAK trigger on my P239 SAS, no complaints, no sore finger.

I love my P220-45-TSS-SAO! It's the full size, but carries well. I've had 1911's in the past. I'd rather have the SIG. I've had no issues adapting to the higher/tighter thumb safety. I'd think the carry model would be just as awesome and loved.