If you can find one, I'd go with a CS9. There are a couple in the classifieds, but I forget the details.

I like the look of the Shield and when supply catches up with demand, I might buy one. Still, I think the 3rd generation semis are overall superior firearms. If you can find one of the rare double action only versions, they are slightly more narrow in the slide area. Which makes them just that much more concealable.