Well I did a good amount of research before I went with the 40c. It's really well balanced for a so called "Compact". Very accurate, 10+1 and it will accept full size .40 magazine to make it 15+1.

I regularly CCW the 40c with the 10 round magazine. I have absolutly no problem concealing it. Jeans, shorts and even with those nice snug shirts I have. I come home and switch it to the 15 round magazine, plus I install a Streamlight TLR-4 laser/light combo and it becomes my nightime home defender.

I also picked up a S&W factory 9mm barrel and a few 9mm magazines and Presto! It's transformed to a 9c. I have fired about 800 9mm rounds without a single hiccup from it. I can see why the 9c is so popular. I have put about 500 S&W.40 through it as well. This thing pretty much shoots like a full size M&P, 5, 10, 15 yards out with ease and confidence. I really can't tell or feel a difference between the 2 different calibers anymore. My accuracy and follow up shots are almost identical now. Which is awesome for me!

In Smith and Wesson I trust! Go with the .40!

And one last thing, You can also purchase a .357Sig barrel for the 40c as well. Can't do any barrel swaps with the 9c!