Installing back up irons will somewhat depend on the purpose of the rifle. If you would use it to protect your life, then I definitely recommend a set of BUIS (folding front and rear). I'm not sure how much hard use your optic would tolerate before losing zero or failing entirely.....and if either of those happen, you've got a problem without irons.
If it's strictly a range toy, and you've got other rifles/shotguns for self defense, then there's little reason (besides practice with them) to install irons.
I've been using Troy's irons for years and have been completely satisfied. In a true back up role, Magpul's set should work just fine.
