I'm new to AR's and I researched for several days and thou I don't want to spend $400 or $500 for a aimpoint..so I have gone with a very popular Vortex Strikefire, there made for the AR platform and with the high rise bracket they are easily ready for cowitness....
Guess it all depends on what you plan to use your AR for most often. If its a home defense gun, how many 100-200 yard shots are you going to be taking in your home? If its for varmint control a little bit of magnification might be needed.
There are a variety of variable zoom red dots out there with a range of 1-4x which is a good mix of the two needs.
I have a 4x ACOG scope on mine. Anything 100 yards and in I shoot with both eyes open. Anything farther out only thru the optic.
I only have the one AR at the moment so it's a mix of both home defense and varmint gun. Being I'm in the high desert and there is amble 200-300 yard shots available, which is why I went with a 4x with BDC reticle.
What are looking to hit out at 200yards? Varmints, man, or groups?
I don't experience with the 223 line but my love all my Nikon glass both scopes and lenses. I believe they have one in that line with less magnification which will work better close in and still let you get good hits on larger targets out to 200. But if you want to bang prairie dogs at the range the more magnification could come in handy.