both, have the Back Up Iron Sights in case the battery on the red dot is dead or you forget to turn it on, the red dot will be much easier to see in a dim or dark room or range than irons.

a HUGE advantage of red dot or scope over iron is that to shoot accurately, one must focus on the front sight, which is very very hard as you get over 40 yrs old, competition shooters (my area of expertise) often use special glasses to focus better, but you lose focus at distance. Dot and scope crosshairs are focused to appear at distance so if you have your street glasses on or don't need glasses you see both the target and the dot/crosshairs in focus. This is less of an issue in a close encounter defense situation (not my area of expertise).

Poole