I really think red dots are the way to go for military and "SHTF" scenarios on the AR. If you'll notice, the military is moving quickly away from the fixed A2 carry handle, and on to flat top AR's with a BUIS and red dot optics powered by batteries. The guys coming back from the sand box all rave about the Aimpoint, which has up to 1000 hours of battery life, tough as nails, drop tested, etc. and the ARMS #40 flip sight.
I'm all for irons, and don't believe a military rifle should be without them, but I like the red dot because it's faster and more forgiving in a CQB environment than any irons, can be seen in low light, works with night vision, and just plain works. Why do I not care about batteries? Because with the AR, you can fix the sights to see through the optic (co-witness) so if the optic fails, gets smashed, batteries do die, etc... then you just use your iron sights THROUGH the glass. You don't even change your cheek weld. There's just no negative to it as long as you have the Back Up Iron Sights (BUIS) that can be used even with the optic in place as long as you PRACTICE with your irons too.
I've owned the ARMS #40, and personally, since I'm just a range monkey, I like the "chopped" carry handle better. I can still move my elevation wheel up or down for those 500 yard sillouettes, and I don't have to flip it up or down ever. It's always right there. With the #40, you don't get elevation and you're stuck with what you sighted in at which in my case is the "Improved Battlesight Zero" of 50/200 yards.
Now if I were doing up an AR that was for longer range work, I'd want the brand new ARMS #40 (L maybe?) that's lower profile than the original to fit under the scopes on the SPR rifles, and I'd want a PRI flip front sight.
BUT a preference is just that, and if you LIKE irons better, then by all means, use them. I just personally like the red-dots, and most newer shooters who weren't trained on the irons only seem to like them better too.