Grabbing a new optic for my issued rifle, got a go ahead and wondering your thoughts before I pull the trigger. Used an eotech for awhile but none of the new ones and no magnifier and also previously had a Steiner 1-4 on a personal 3 gun rifle. Another question would be is the vortex rugged enough?
Would be no more than 500 yards shooting but identifying things at distance is always a plus and would be an m4 so 14.5" with regular m855a1 ball.

You want a 1-6 (or greater) optic for 500 yards and in period IMO. The RDS + magnifier is a bandaid solution to see better out to 3-400 but primary situation calls for CQB IMO. As far as the Vortex 1-6 goes it's really heavy but a great optic with excellent glass and bright illumination and a stellar FOV on 1x. If you can handle 2 lbs of optic (most mounts are around 5-7 oz) then Id say go for it. But I would look for other options. ETA: didn't see the ruggedness question the first time around but yes it is durable as hell. There are very select individuals overseas that use them (the kind that get to pick gear out of whatever they want to) and that's enough endorsement for me to consider it G2G for any civilian applications(HD, 3gun, hunting not the best for hunting due to weight, LE etc)

What type of environment will you deploy the rifle in the most?

Urban environment: Go with the red dot and magnifier combo. No scope shadow with the red dot when shooting in various positions and it's very quick and accurate. 

Rural environment:  Variable optic wins. Find one with a daylight bright reticle.