I enjoyed playing through Dawnguard however there have been issues with it that has lessened the experience. First I had come across several major lag periods. In the ruin leading up to Serana and also when she first follows you outside. I did find a fix; It required me completely restarting the game. I have also has several lag issues since. Another, and one of the most annoying, is the infinate loading screen. It seems to be random, but I've waited about 5-10min with no luck of it loading. Another problem is that the game will freeze quite often. It happened to me at least 6 times as I went through it, and as I talk to others its obvious I'm not alone in this. Finally this didn't happen to me, but a friend where Serana would be stuck in a certain building inside the soul carin. I guess in order to get her out he had to keep using unrelenting force to blow her out of the building. I guess she was in there for about an hour.