If I wanted more than a 9MM (and I don't think that's necessary at all, but I do think it is desireable) I'd go the .45 ACP, and I would look no further than these calibers in an S&W Shield.
There are lots of good guns, but for me, since any concealed carry gun is going to require some compromises, I choose what's best for me that fits my hands best, that is easiest to carry, and that I can shoot the most accurately. It goes without saying that the gun must also be very reliable and with all these things in mind, it must also be cost effective. My personal experience with the Shield 9 and to a lesser degree with the Shield .45 has shown them to be the most acceptable choice that meets all of the criteria listed above. I've got (with my wife's help ... she has a Shield 9MM) well over a thousand trouble free rounds through the 9MM's and over 500 rounds through the .45. I've carried the 9MM almost daily (except for the days I've carried my S&W M640 J Frame) for about three years. We've had my wife's Shield for about two years. Mine was bought used and her's was bought new. They have given us no reason to consider retiring them as our personal protection weapons. They carry very easily and they are big enough to properly hold and they are plenty accurate and have been very reliable. The 9MM ammo is a bit cheaper, and the premium stuff is plenty effective enough to satisfy our requirements. Both my son's own Shield 9MMs, and they have also been very pleased with them.
I love my revolvers, but the Shield is just a bit easier to carry daily and it allows a few more rounds of ammo on board with easier, faster reloading capabilities. Bonus is that getting the Shield into action is basically no different as compared to my favorite revolvers. It took me nearly 50 years to make the change to semi autos, but I have given up nothing but my nostalgic preference for the revolvers for this duty. You've gotta choose what suits you best, but choosing the S&W Shield is as good, and I say better!, choice from among what is available. There are not many bad choices, but the Shields have been the very best compromise for us!