All in all I was happy with this DLC, on the whole it was very much like Knights of the Nine. I do wish that once the whole quest line was over, the respected "castles/forts" actually cleaned themselves up. That or Beth should have included an options to bring the "forts" back to life, basically in the same way that they had us recruit some new members.
The Lost Vale doesn't have the same awe inspiring I can't tare my gaze away like Blackreach does, but I really do like the Snow Elf architecture, in ways it looks a lot like the Ayleid architecture from OB.
Each factions quest's line could have been more unique, instead of basically the same thing just different sides. I'd give the DLC a 9.0 out of 10.0.