I'll go peer through both of mine and post my thoughts.
Sorry for the delay.
It's a cloudy evening, the sun is behind the mountain, and it's barely past the red sunset colors, so I'm checking the scopes right now. With the illume on both are usable at 4x but of course it's easier to see the DMR reticle. I could make any reasonable long range shot on a deer with either scope.
Without the illumination on if I were shooting a blackbear , nope I couldn't see the 4-20's reticle well enough but probably could shoot a deer. I can still see the DMR reticle on my black plate though whereas the 4-20 mil reticle is getting tough to see. Such a huge difference in reticle thickness.
As far as brightness the 4-20 is a hair better in low light on 4x but if I don't have the illumination on, thus not seeing the reticle well, it's for not.
Don't get me wrong I like my HG2 4-20 but it wouldn't be my first pick for low light.
The DMR reticle has to be down to 2x for the reticles to be close to the same size, well it's still easier to see the DMR reticle on 2x if comparing.
I'd spend the extra money and go for the Ares BTR G3 2.5-15x50 if I was to decide between that and the 4-20. One wouldn't think .1 mil thicker would make a difference but it does and the illuminated cross in the BTR G3 seems faster to put on target more intuitively. I keep on saying it but this BTR is a killer scope and the IQ is nicer.
The DMR is the way to go for hunting IMHO. Gotta see the reticle at 4x without illum on this can't be beat and with illume on its even better.
The lesson here for me is one has to make out the reticle and Illumination on made the biggest difference by far.
Really too bad we don't have a higher end scope like the DMR!!!