Frank, Glad to hear you like the build. It was a blast to play and is honestly one of my favorite playthroughs to date. In answer to your question, I contracted vampirism through the storyline. The most exciting part of the playthrough is acquiring new powers and seeing what new moves and strategies in gameplay that gives you. Starting off with vampirism takes away from that excitement in my opinion since you would posses some of your key powers from the start. Plus, acquiring it through the quest line gives the build a reason to seek out the dawnguard as his means of contracting the gift of vampirism. Thanks for the compliments on the build and if you end up trying it out I'd love to hear what your experience is.