did anyone get a reward for doing the reaper quest? and whats the reward for finding all of jiubs pages(realized imediatly he had a suprising resemblance to a certain character in morrowind)

Sorry, off topic a bit... Can you still go into Soul Cairn if you side with the Dawnguard?

havent actually tried but i dont see why not. ill try a bit later you probably just have to fast travel to the balcony and go back from there

I sided with dawnguard and I was still able to go back in.

Jiub in the Soul Cairn is the same Dark Elf from Morrowind. The Cliff Racer slayer...

And as far as rewards... well it's really the thrill of the fight against the reaper

And both Dawnguard and Vampires get access to the Soul Cairn

^^ This. You can go back.