Its better to have them and not need them then to need them and not have them. I also love having BUIS too in case i take off my optic and put it back on, I can re-zero, right then and there. also vice versa with the Iron sights, i can take them off and then re install and verify Zero right away. Last time i was at the range I zeroed in my irons and then zeroed in my Optic. When i got home I realized my optic was a little crooked and the mounting nuts were loose, i must not have tightened them down all the way. when i re tightened down, When i cross verified, the red dot was a bit over to the right. if i was shooting at 100 yards it would have been off by about 12 to 14 inches. now without the BUIS, i would have to wait to get to the range again to re dial it back in. I just flipped up my rear sight clicked the dot back over to dead center on the front sightpost and 30 seconds later i was re-zeroed.
Although it may be a rare occasion that the RDS fail but it is absolutely possible. If it did, and you had iron sights, you could put your new or fixed optic back on and re-zero it right away. If its just a range gun then who cares if you have them or not. If you think there is ever a possibility that you would need to rely on it for real defense then BUIS are a cheap insurance. I used to have a stevens 200 in .308, and i remember when i first got it it didnt have a scope mounted on it, i remember thinking how worthless the gun was without it. After having it for awhile I used to think "this thing is awesome with the scope, but it used to drive me nuts thinking of if I was depending on it and the scope broke, it would go from a tack driver to a extremely short range .308. That and I also got bored with the killer accuracy, ha ha. I sold it and replaced it with converted Saiga .308. I love the fact that i have the scope on the saiga, and shoot it mainly with that for long range, but if anything happened i could take the scope off and have a perfectly functioning battle rifle with irons.
Last edited by SKSer; 10-28-2012 at 12:16 PM..