Re: H-59 or G2dmr...?
Ronin, what are you planning on doing with your reticle? To dial or to hold seems to be a hot debate around here and you will find a verity of opinions supporting the merits of both but I think you are going to find your choice of reticle is going to hinge on how you are planning to employ it and how comfortable your are with it.
If you are planing and are more comfortable with dialing rather than holding, you will probably find the H59 a bit over kill and unnecessary. That being said if you what to hold and or dial then I would highly recommend the H59.
Many folks who are use to shooting traditional reticles find the Horus reticle overwhelming. They often find the reticle distracting, busy and confusing. My first interaction with the Horus reticle was a little over a year and a half ago when shooting a XM2010 with the Leupold Mk 4 ER/T 6.5-20x50mm M5A FFP (H-58) at work. My reaction was "WTF is all that shit" But honestly in took me less than a day to fall completely in love with it. Unfortunately that XM2010 was only a demo gun so the following week my teammate and I both ordered our own Mk 4 ER/T's for our up coming deployment to Afghanistan. That optic has been on every sws we have from the mk12 to the m107.
If you need to engage non-static, man size targets in rapid sequence and at multiple ranges, I can say hands down that the H58/59 is the best Mil based reticle out there. Our last engagement with enemy forces resulted in 4 EKIA and 3 EWIA in less than 10 minutes, at ranges from 1590m to 2160m while utilizing the m107 and Mk 4 ER/T 6.5-20x50mm M5A FFP (H-58).
After reviewing the G2 I can say that it would not be adequate for utilizing pure holds. The reticle tree is not nearly wide enough to use at extended ranges in high winds. As a matter of personal preference I also find the .2 Mil subtensions of the H58/59 to be more useful than that .5 Mil's found in the G2.
Many folks have also state the fear of not being able to see the splash from missed rounds due to the "cluttering" of the H58/59. I supposes there might be some truth to this if using extremely light projectiles at extended ranges but under most normal circumstances I didn't find this to be the case. The lightest caliber rifle I have used my H58 with was the mk12. The impacts of the 5.56 projectiles could easily be seen out to 1500-1700m during the dusty summer, 1000-1300m was reasonable for the spring time before the ground dried out and about 700-900m with 2-3 ft. of snow on the ground during the winter.
Hopefully this gives you some insight. If you are willing to adapt and you have the time to invest in to learning how to use the H59 I would highly recommend.