I just picked this up ... hoping for a bit of coherence. I think the concept of a campaign based on a series of expeditions into Undermountain, which neither require nor expect the entire thing to be detailed, is a pretty good one. So I didn't come in expecting the entire mega-dungeon to be detailed.
But I'd at least like the product to be self-consistent, so when I start playing off the colored-in parts, it stands up. The maps are horrible ... the "ungeon Level" map doesn't correspond to the blown-up portion for the first adventure. The scales in later maps are wildly off ... the "Farm Level" is supposed to be huge, by the despcription, but by the map and scale it's actually tiny, but is dwarfed by a couple of sub-levels that are full=page maps at 1:20' scale. Maybe the farm level map is an excerpt, like the Storeroom Level excerpt ... but then it should at least say so. The map of the Yawning Portal Inn doesn't even have the Entry Well on it! Gee, you think you should put the primary feature of the entire building on the map?
At least the first adventrue is fairly well scripted, but the entry to the second is much less so. I've become so dissappointed I've given up reading for now. It's like the product was designed and built by committee, and they fired the editor part-way through.
Luckily, a few years back I bought pdfs of all the Undermountain products, which are much more coherent and have much more detail. I was hoping for a couple fo updated mini-adventures with a set of convenient interlinked maps of the whole complex ... and I've been disappointed.