I played the game through a few weeks ago. I explored the whole island and did most of the quests, excluding the one in the infected zone. The playthrough took me 48h 47min. It got a bit tiresome and repetitive towards the end, but all in all I found it an enjoyable experience, and I'm definitely looking forward to the sequel. That being said, I hope some things will be changed, like toning down the amount of running infected. Which is the main reason I'll probably never complete Ryder White DLC. They were sometimes a pain in the ass in the prison as well.
There were some annoying bugs as well, like a weapon disappearing from your inventory after modifying it. It happened two times to me, but luckily I could revert back to the last checkpoint, and didn't lose an exceptional weapon. And sometimes the directions for your next objective in the map just disappeared.
EDIT: And during a mission in the prison, I was transported to the objective room after dying, which actually turned out to be a good thing, as I managed to avoid a confrontation with a bunch of those running bastards.
Funnily enough, you could block a Ram in the prison by shutting the bars before him. It would have been awesome if he had been able to charge through them.
I also found the cutscenes somewhat odd, as all of a sudden there was a group of people with me, while I travelled through the game alone. It kinda ruined the immersion. Hopefully they'll provide a different set of cutscenes for single players the next time, although I doubt that will happen. BTW, for some odd reason Xian Mei's voice actor sounds totally different (and awful) in the cutscenes, compared to the gameplay sections.