Heres the deal.
Your close in (CQB range) optics should be set for 25 to 50m max. Your BUIS should be zeroed for the 25/300m or 50/200m (whatever you prefer to use) just like your normal iron sights. This way you have close and battlefield sight options without having a red dot completely obscuring a target at 300m. Aimpoints,EoTechs, etc are great close in sights, but I have found them less than desirable at further than 100m range. If you want one optic that does both, you need to go for an ACOG(3X or 4X) or an Aimpoint and an Aimpoint3X magnifier in a fold away mount like the one from Sampson.
Just my opinion based on trying lots of the goodies out there today and over 16 years military service. All in all, other than the CQB Stuff I do, I still prefer good 'ol A-2 iron sights for every-day any condition use.
Go with whatever works for you, just dont limit yourself and look at all the options.