What is a good 2X red dot sight for AR-15 under $400?

[Kurbsky]

What is a good 2X red dot sight for AR-15 under $400 (including mounts)?
I did some research on the Internet but only found very expensive staff like Aimpoint or really cheap staff - Barska and below of dubious quality and nothing in between. There is a good value Burris that is $300 with mounts but that's 3X magnification, not 2X. There is plenty of options for 1X red dot sights but I am wearing reading glasses and ideally for short range need 2X. Thanks...

 

[Ronbo1]

Vortex

I have a Vortex strikefire and really like it. The only bad thing I can think of is the on off switch can be bumped in a rifle carry case. I just take the battery out when not using it. Choice of two mounts with it, high one for AR15. Comes with a 2X doubler that can be used with or without.

http://www.vortexoptics.com/product/vortex-strikefire-hunting-red-dot-scope-low-30mm-ring

 

[Superhouse 15]

I have several Tru Glo 2X optics. The TG8030B2 fits what you're looking for, as does the TG8030MC2


http://www.truglo.com/content/products/firearm/red_dots/traditional.asp
http://www.truglo.com/content/products/firearm/red_dots/reddot_dual_multiple.asp

 

[45Gunner]

If you have a really nice rifle, one that costs big bucks, why scrimp on a scope? Put something decent on there like a Trijicon ACOG. You can take the butt off a fly at 100 yards with one of those.