In the spring I planted 2 grafted Cherokee Purple tomato plants in hopes that they would be resistant to late blight as advertised. Well, they did great at first. I had ripe tomatoes earlier than ever, mid July. But I think that was purely due to the fact that they were started earlier and were growing in bigger pots, hence a larger root system.
When late blight hit, it hit the grafted tomatoes the same, and maybe a little worse, than the Amish Paste tomato plants.