One question I have not seen is how accurate do you expect your AR to be, OK it is new, but there are some out there that can not ever be better than a 2.5MOA rifle (with match ammo) and others that get sub MOA all day with surplus ammo.
Second question is at what range do you expect to shoot?
If shooting targets, are we talking plinking or competition and what sort of competition? In some matches you are forced to dial the magnification down all the way and tape the power ring in order to be allowed to compete against some of the iron sighted rifles.
Oh yea how fat is your wallet? Are you willing to spend as much or more for your scope as you did for your rifle?
Without knowing answers to these questions I can say that a 3x9-40 can be a good choice, just make sure it is well known for clarity.
I have several of these I got at various sales and they have worked well for M-4 hunting rifles and .22s
I also like the 1 piece mounts Rock River started selling a year or so ago as opposed to having to mount a riser/ring combo or getting extra tall rings.
Being one of the top 2 most likely to be modified rifles in the world (ruger 10/22 is the other) yo have so many options and variations open to you that you can spend loads of money and weigh your rifle down until a M249 looks like a light weight nest to it.
Keep in mind some things......
How accurate is the rifle really? If you are getting 3MOA out of it, you probably do not need a 24x scope just to watch your 3"+ group from really close up.
What will your maximum effective range be? I know what the army lists as the maximum effective range, but keep in mind they are talking about hitting a target 15" wide by 24" or so tall with enough accuracy and energy to wound. Personally I find a long kill shot on a whitetail to be 300yd.
Do you intend to hunt with this rifle? How much weight are you willing to cart around over the hills and through the brush.
Mil-dot and target turrets are not strictly necessary, can you guestimate range using the old MK-1 Eyeball? Can you estimate the amount of bullet drop at that range and compensate by aiming a bit high?
My takes on a few:
(By the way I am assuming an M-4 pattern AR versus LRT)
Trijicon ACOG, does the job, light weight, clear, sturdy,external illumination, +1 on coolness factor, can cost as much or more than your rifle
Eotech Assume light weight (can't find weight), somewhat easy to use, gotta remember to turn it on... a bit pricey compared to your other choices, NEEDS batteries, listed good for 600 hours, but watcha going to do when the temperature drops below freezing and your battery lifespan does the same? Or you are out in the boonies and the battery finally dies? Sorry I do not have to keep my spare batteries in my underpants and then have to switch them out with the ones in my sight every 10 minutes lest the sight quits working. Accurate enough, My buddy uses one to zero soda cans offhand @50yd and seems to get 3 out of 5.
Of the two the scopes you listed, the Leupold is lighter on the other hand there are several scopes here that would do a good job.
Truthfully I would feel good about putting any of the first 3 on an AR platform, and taking the difference to buy other stuff, slings, ammo, cleaning supplies memberships to private shooting clubs........