Aimpoints are tough as nails and have excellent battery life - you can leave them on for years before you have to replace a battery.
I've equipped my AR's with Eotech 517's for the reticle. I zero at 50 yards (as opposed to 100). The center dot of the eotech is on at 50 yards, and I can use the bottom tick on the eotech outer circle reticle as an aiming point zero around 10 yards, as the bottom of the outer circle compensates for mechanical offset at shorter distances. This, with the 50 yd zero is a very popular setup for CQB / Combat applications. I also have a folding rear sight, and a post front sight. I leave the rear sight up all the time, and the 517 is a lower 1/3 co-witness.
I also have a primary arms micro dot sight. These are also very durable and reliable at a much cheaper price than the eotech or Aimpoint. It isn't on my duty guns, but is on a training rifle - I've never had a problem with it. They have risers for absolute co-witness or lower 1/3 co-witness. Personal preference, but I much prefer the lower 1/3 and leaving the iron sights up all the time. It's a good combo.
https://www.primaryarms.com/Primary_Arms_Micro_Dot_Removable_Base_Gen_II_NV_p/md-rbgii.htm
https://www.primaryarms.com/Primary_Arms_Advanced_Micro_Dot_with_Push_Buttons_p/md-ads.htm