I have one, and maybe I just got a good one, but personally for their price range, I think the glass is pretty good, bright, clear, holds zero (on my .223). I dont use the turrets on mine so couldnt tell you how it tracks, but have moved it to a few rifles and it re-zero's and holds just fine.
I personally think for their price point they are a decent bang for your buck.
I haven't tried the redfields or the diamonbacks which I have heard great things about and suspect may be a better bang for your buck (just from what I have read).
But again, from someone who has tried the Nikko, I like mine.
Never mind, see my comments further on down.