I'd rate it a 8/10.
The one thing that bothered me, was not about this movie, but about what other movies and conditioned me to think.
There were a few moments where the normal crap movies we see all the time would have erupted into violence or gore, and thankfully "Labor Day" was true to its story and genre.
I enjoyed it.
I thought the same thing after the movie was over. A few times, I thought I knew for sure which trope they were going to go for, and then they didn't. Kept it relatively low-key most of the time and didn't go for the flashy cliché way out. I appreciated that about the movie.
Especially in the end, I was sure that Adele had died before Frank got out of prison, the way Henry was talking about the letters and the camera first focussing on a rock in the front lawn of the house instead of the house itself – I thought it was a memorial! I like a happy ending every now and then so I was glad they didn't go for that additional bit of melodrama in the end.