ive got mbus and MI sights along with matech. the MI are very good very solid my only issue with them is the big aperture on their rear sight on the model i have. the small one is nearly too large to be useful.
the mbus are very wide and block a lot of the field of view. they are extremely durable more than you might think from plastic.
matech are the best rear sights ive come across for the ar15 to date outside the A2 style sights.
the BEST back up irons are the national match sights RRA offers. but they dont fold down.
"Gun control: The theory that a woman found dead in an alley, raped and strangled with her panty hose, is somehow morally superior to a woman explaining to police how her attacker got that fatal bullet wound." — L. Neil Smith
The problem with being stupid is you cannot simply decide to stop doing dumb things...
"I crapped my pants to avoid the draft!!" -Ted Nugent