I have both. This year late season muzzleloader at very last light the Optika6 was a tad bit better than the Optika5. I absolutely love the Optika6, I have 3 of them now and will be buying more.
I just put an Optika6 on a Daniel Defense V7 LW, initial impressions are very good. Right now, I'm putting in 60 hours a week, so I'll have to wait a couple more weeks to see how it goes with it.
I'm thinking of buying another one for a different AR if this one turns out to be what I like.