I was against VAR before the tournament, but I think it has certainly helped. I don't think as many of the lesser nations would have got through, some of the VAR decisions certainly helped in the early games with penalties etc which probably wouldn't have been awarded.
It's still in its infancy and I agree with @Cereal Killer
above that people need to let go of the Greizzman incident. It clearly needs more time to bed in and perhaps 3 calls per team per game would be a good idea as well to limit using it all the time, although it wasn't used greatly in the tournament.
I think also the VAR technicians should have a certain time to communicate a key incident to the ref if he missed it like a clear penalty, a dive or whatnot for the ref to take a look at.
I'd like to see it in the prem and I think it would help the rest of the league more.