Re: 1-6x vs ACOG
I ran an ACOG TA01 for a long time during my stint in the Iraqi sandbox. In the DMR role, it worked okay for short and intermediate ranges out in the open for short periods of time. My biggest complaint with the ACOG was the infinite parallax, which relies on your own eye to adjust to the sight. This is foolproof and reliable, but it's also a recipe for eyestrain and a headache. I spent a lot of time in LP/OPs in Indian country watching goat farmers and random cars drive around. We only had one set of binoculars in the truck, so I used my ACOG. I got a lot of headaches and it was difficult to do long stints behind an ACOG with its parallax setting. Other than that, it was uber reliable. The eye relief on it sucked terribly though. 1.5" is annoying.
I've messed with the BAC models, and they work much better for CQB. The standard non-BAC models of ACOGs are pretty worthless indoors in CQB conditions.
If you want a good 1-6x, there are three excellent options out there with SWFA, Bushnell and Leupold. I would personally opt for the new Leupold Mark 6 1-6x, which is what I'm going to do when I pick up a SCAR 17S. Having 1x is great for CQB and rapid fire, and having 6x is excellent for long range. There is a drastic difference between 4x and 6x in terms of what you can see.
I say get the 1-6x.