Like others have said here, you've answered your own question. If that's
what you're used to, go with it! When I purchased my M&p40C, I wasn't
aware a thumb safety model was available, plus I was hot to trot after
already waiting several months for a 40 Shield. I'm trying to get in the
habit of carrying a round chambered, but its hard with the little voice
in my head saying "there's no safety". I realize what a slim chance I might have of drawing, racking & then firing in a bad situation...but there is still that little voice.