I almost always use the Russian holo, somewhat of a trademark. I use it because it looks like proper optics of days gone by instead of the sleek look the others gives which to me is a more appealing silhouette from a side view of the gun in particular, my cherished L85 with a US holo looks a bit like a toy to me but looks right with the Russian one so I use that and that trend follows for me on alot of guns thought not all. In other words I basically choose the sight I think makes my gun looks best, regardless of function because frankly if I see you through my sights it doesn't much matter what shape the crosshair is.
Regarding the 7x, this is a really good scope for something like the M40 where you have a faster cycle rate and much more mid range ability, the slight reduction in zoom means you can simply see alot more and keep track of your target better also works well with a straight pull bolt. Put another way it's the best sniper scope to be aggressive with and not just sit back bipod up and such, that said the ACOG is also really good for this aggressive style and you don't have an annoying glint on that. The 7x is basically the hybrid scope in that respect, it's good for sniping though not great and same for mid range which makes me gravitate towards both it and the M40 as I can hit long shots but I can still stay with my squad mates and do something useful without just resorting to the M1911 (though the 1911 is actually a great standalone gun to be fair).
