you still require a quick acting meal time dose and a continuous background dose, the pump can do both at the same time.........
so you will program in your background delivery rate, for example, 1 unit an hour.......this will likely turn out to be many rates over different times of the day..........its this delivery of basal that makes control much more accurate.......you will eventually be getting the exact amount of background that you need, which in turn allows you to achieve accurate mealtime/bolus doses........
overall this means less insulin going in that you would of been previously used to with injections.....this for me was the most noticeable change......