My EDC is a M&Pc and I have looked at the Shield several times as a "slightly thinner version" of my EDC.
Both the Shield and PPS are close in size and weight. Both are accurate as all get out ( my personal feeling is that the PPS is more accurate but that only counts on paper targets). Both feel good in the hand. If you're left-handed like my wife you might like the PPS mag release better. Even as right hander I love that mag release, but a lot of people don't so personal choice.
I think the Shield is a little less expensive but I have seen the PPS for as little as $550 around Houston.