I've owned a gen 1 Shield 9MM and a gen 1 M&P 9MM. Both are serviceable, but ho hum guns. They both are long gone.
I have a gen 2 M&P 9MM, and I far prefer it over the gen 1 model. I do really like this pistol. That being said, it will never replace the numerous Glocks that I use for home defense and conceal carry. It mostly just sits in my safe, although I did use it in the night stand for a year or so.