I own both the 9 Performance Center and just recently picked up the Performance Center in .45. Carried the 9 for a couple years, put well over 1,000 rounds through it and less than 5 failure to feed/eject. It was bad range ammo coupled with well over a couple hundred rounds through it at one time.
.45 Shield is surprisingly easier to control than the .40 cal. I rented a Shield .40 at the range and also spent some time with a Glock .40 that my friend who is an Albany Police officer carries and this .45 Shield shoots better than either of those two. I like the .45 because you get a much more powerful defense round than the 9mm, and only lose one round of capacity. S&W did an absolute fantastic job designing this gun, as it is almost the same size as the 9mm and carries almost the same. I barely notice the difference. Springs in the mags are super stiff at first. I loaded them up with range ammo and let em sit loaded for a couple days, problem solved.
As for holsters, I run a Galco King Tuck and a Galco Combat Master (yes, I am a huge Galco fan), depending on the situation (how deep I need to conceal that day).