Like 94lt1 said, you will get text messages with data off but you will not be able to open a pic in a pic msg with data off. You will still get the text message saying that you have received a pic msg but when you go to open the pic it will stay on a continual status of "downloading" until you enable data (took me a long time to figure that one out)!
I am currently trying smart actions for the first time. I had been using JD. Like when using JD, I only set the basic settings (turn off wifi/data/gps when screen off and night time mode, etc). So far the difference has been an average of 24 hours on JD and currently, my first full round with SA, has been 33 hours with 27% battery left.