I've hunted 16 states and Mexico, striking out in 4 of the states. It's hard to rate hardest and easiest with factors like public vs private land, hunting pressure and bird populations.
My easiest hunt was Oklahoma private land with plenty of responsive birds. The first afternoon I roosted 90 birds, 13 of which were gobblers. Me and my 2 friends tagged out with 3 birds each.
I found the hardest to be Alabama public land, where I didn't even come close and ate tag soup.