I'm currently 7 sessions in to a Dwimmermount campaign. While the dungeon itself is remarkable, I would say the same of Barrowmaze, in which I've also run a campaign. What has set this experience apart is the Dungeon Tracker. I have a copy printed and laminated, and I keep behind my screen the two sheets appropriate to the level that the characters are exploring. Being laminated, I'm able to use wet erase markers to easily make notes and track time while having all of the most necessary details of the level right in front of me.
While I still keep a copy of Dwimmermount open on a small table to my side so that I have access to detailed room descriptions, the Dungeon Tracker seriously reduces the amount of page flipping I have to do during a game. That has translated into a tighter game and a more enjoyable experience for the entire table. The Tracker has also allowed me to keep my notes on the dungeon much better organized. With Barrowmaze, my copy of the book was littered with Post-It Notes, one per room that the PCs had explored, on which I had written what PCs had taken and defeated, what was left behind, and what may have moved in afterwards. Using the Dungeon Tracker with Dwimmermount, I can do a better job of maintaining a living dungeon environment while spending less time doing so.
I don't know how much value the Dungeon Tracker would have in purely electronic format, but printed, laminated, and perhaps bound using coil stock, I've encountered few game aids that come close to providing this much utility. For a referee running a game in Dwimmermount, or for anyone interested in tools for helping games play as easily as possible, I'd give this a very strong recommendation.
[5 of 5 Stars!]