I have both the 9c and the Shield. Love them both. Both shoot well in my hands. Interestingly, I use the largest grip on the 9c, even though my hands aren't especially large. The Shield fits my hand great, but the 9c points much better with the large insert. Noticeably better than the small insert, which is more like the Shield. Don't really understand that, but, oh well.
The 9c is my "favorite" carry gun, but I have wound up carrying the Shield more than any other. The weight difference is significantly noticeable to me, and the Shield is better for me for summer carry. I typically carry it in a cargo pocket when I'm wearing shorts. We'll see if I go back to the 9c now that it's cooler.
Also, I find that with the Shield, I have no problem also carrying an extra mag. With the 9c, I usually don't carry a spare.