I have it, but I haven't really delved into it because I need to get off my butt and finish making an organiser for the whole bloody game so I can make it playable. From what I can tell, it is basically along the same vein as the other big box expansions - more investigators, 2 Ancient Ones, an adventure deck, too many unique asset cards, specialised condition cards etc. More bloat, but too early for me to say if it did add anything unfortunately.
I'll keep you message in mind next time I put it onto the table and do a dreamlands run, the only thing holding me back is making two more organisers for the games, and especially one to organise all of the smaller cards to be a little more manageable. The Unique Assets deck for instance is just too unwieldy, and I don't understand the decision to create that deck on top of an artefacts deck plus a normal assets deck.