EOTech's have proven to have issues:
http://soldiersystems.net/2015/09/30/ussocom-issues-safety-use-message-eotech-enhanced-combat-optical-sights-plus-goings/Now they are probably fine for "red dot" use, but for adding a magnifier, and whatnot, they're unsuitable...
For a budget conscious solution, I highly recommend:
http://www.amazon.com/Bushnell-Illuminated-Reticle-Riflescope-Turrets/dp/B00AU6EIIY/It's ffp, so the bdc reticle is always on target at any magnification. The reticle is illuminated also. At 1x you get a horseshoe/circle w/ center dot, and then upside-down Ts beneath it for ranging... You can't see the bdc very well, so it functions like a red dot at 1x. At 4x it functions like a standard magnified optic.
Also, and importantly, all adjustable magnified optics can be adjusted to intensify/brighten light during low light situations by playing w/ mag levels -- generally around 3x is brightest point...
Now others do make similarly featured ffp optics w/ 1-6x magnification, primary arms and bushnell come to mind at sub $1200 range, but nearly all are at that price level (read: expensive).
For an all purpose optic on a 5.56 gun, I personally really like these adjustables. Yes, definitely heavier than red dots (but not significantly if accounting for a magnifier) and also heavier than fixed magnification optics as well (again, not too significantly).
The elcan that IMO is one of the finest military grade optics out there is 1x and 4x fixed magnifications. The meopta optic that shipped with some of the Czech Military issued guns was 3x.