I've read the first three Gaunts' Ghosts books and the first three Eisenhorn books by Dan Abnett. I thought that they had some good parts. They were good enough to finish even despite me being two decades removed from puberty.
I also read "Hellforged", because it was about the Necrons, and they were my first army. That was pretty terrible. If I was 11 though, I might have liked it a lot.