Well look what just arrived!
I've only had a brief chance to flip through it but so far it looks like a really well put together book. The binding feels good so far, and I haven't seen any odd printing issues or anything like that. This book is big! A bit over an inch thick, but well laid out and so far it looks pretty well organized too. I'll read through it more over the next few days and then maybe give some more concrete impressions. But so far I like it.
The Illustration Book is smaller than I expected. That's not really a bad thing, just a little surprise (I probably shouldn't be surprised I'm sure the size was listed somewhere). The illustrations are pretty cool, with a lot of different artists with different styles represented.
Now I just have to wait for my physical copy of the Dungeon Tracker to arrive (I've been told that'll be coming in a separate shipment) and the project will be complete for me!
If you're interested in Dwimmermount, but didn't back the Kickstarter, you can get PDF's of all of the books at Drivethru RPG. All the different books are between $5 and $10 there, which I think is a pretty good deal for a dungeon this big!
I believe physical books should be for sale to the general public in the next few months as well.