Re: Best sights for ar15:
The big 3... Aimpoint/Eotech/Trijicon.
Have not shot the new trijicon srs yet, but looks intruiging. Own other 3. All fantastic.
I give the nod to my trijicon acog ta33 horseshoe reticule. So fast while moving with bindon aiming concept..and when you stop and close weak side eye you get the magnification benefit. But at over $1000 it is not for everyone.
However, if price is an issue go with an Aimpoint PRO. $400 for simple, rugged and reliable. Fabulous battery life as well. I trust my life with this one at work every day. Eotech a close second for the under $500 group simply because of battery life. I love how both work and how reliable they are. Wife thinks eotech is better...fwiw..and she's a heck of a shootist.
If you stray from these 3 brands you are on your own in my humble opinion. Military and law enforcement choose these because of their sturdy design, simplicity and reliability.