Had mine for about a year now, and to be honest, for the price, there's not much to complain about. For me at least, the worst part of the lens is the removable lens hood, which is made of cheap bendy plastic, and because you can distort it in your hand, can sometimes make putting it on a little tricky.
TBH though, I'm nit-picking. I use mine on a D810 and a D750, and it's tack sharp on both (even very good wide open at F6.3). AF is quick and positive, VR is superb (and in some cases better than Nikon's own implementation. Zoom action is very smooth and the colour are great.
If I really had to criticise the lens, it would be 1) the switches on the side are a little small and can be a touch hard to move (especially wearing gloves). Secondly I've had a couple of issues with the AF stopping working and needing to re-seat the lens, but to be fair it hasn't happened for a good while now.
Long and short is would I purchase it again knowing what I do now ? Yes, absolutely 100%