They aren't a magic bullet that will solve all the G&T problems, but IMO they are a fantastic step in the right direction.
I suspect that they will be up and running too late for my DC to benefit but at least other children will have the chance to do a bit more than just follow the national curriculum because that's all the school aims to do.
I never liked Theresa May, but had she let people know that she would reintroduce grammar schools, I'd have been willing to campaign for her.