Of all the "affordable" military-grade optics, I chose the AimPoint PRO.
Not only for the price -- usually in the $400 ballpark -- but it also came with a mount. Many other models you need to buy the mount separately, making those optics cost even more.
It's rugged, can be used with the flip covers closed if you have both eyes open, and the battery lasts 3 years while kept "On" at the lowest illumination level. It has night vision settings so the dot is visible through NV goggles, and the battery hatch is accessible without needing to remove/re-zero the optic.
The battery is the very-easy-to-find DL1/3N camera battery, which comes with the optic. Some optics may use Lithium batteries that you can't find at Walmart or Long's.
It's a little on the bulky side, which adds some weight to the gun, but only by a couple of ounces. The specs state 7.8 oz for the optic alone. For comparison, the Micro T-1 is 3 oz, and until recently sold for almost $900. Now it's listed on the AimPoint site for $499. For that price, it looks like it comes with a pistol mount for Ruger Mark III/IV, but you have to buy a standard mount separately for an AR rail. That's listed at $92.
I have 3 PROs, and one matching 3X magnifier. The magnifier is more for precision shots and helps with zeroing the red dot at the range. Less challenging to get small groupings with older eyeballs. IRL, I can see using the magnifier for varmints and hunting small game. For home/self defense, better to go 1X and keep both eyes open.
I also splurged for the rubber protector to preserve the finish, mainly if I decide to sell any of them.
I didn't buy the Kill Flash lens cover. it's designed to prevent refections that the "enemy" might see. For $50, I'll take that chance!
The magnifier reminds me of Jurassic Park
, when the kid, Timmy, is playing with the NV Goggles in the car.
Lawyer: "Where did you get those?"
Timmy: "I found them under the seat."
Lawyer: "Are they heavy?"
Lawyer: "Then they're expensive. Put them back."
The AimPoint 3x is quality glass, which you can tell by its weight. The AimPoint quick-detach twist mount was purchased separately. Not cheap, but cheaper than most other brands.
No matter what you decide, check all the specs before buying. Make sure you know what mounts are included. Even if it comes with one, the one included might not be what you want. Prices for aftermarket top-tier mounts run upwards of $250 sometimes. Factor in battery location, too. Changing one might require a re-zeroing when removing the optic.
Hope some of that is helpful.