I think she's pretty cool, although I think I may wind up joining the Dawnguard, eventually. As cool as the vamps are, I don't think I wanna block out the sun and watch the world die off; the place would probably wind up being the next Nosgoth from Legacy of Kain.
Yeah, I know. I've played the vamp side, although I haven't beaten that part, yet. Since I've been busy with other things. xP
It's just, personally, I don't like the concept of continuing to serve Harkon, and I don't see the actual need of blocking out the sun. There's enough caves to hide in and regenerate in after a battle during the daylight, from my perspective.
Why do we really need to block out the sun? That's just my reasoning; even after all of the drawbacks of being a vamp. >w<
Brain died, sorry. You actually can join Serana or his side after... getting something that you need to use to block out the sun. So you can either betray him and join Serana or betray Serana and have Harkon betray you.