I'll likely limit my WOTC product reviews. Typically I'll be getting much of the new release stuff a month or more after most people have had a chance to wander down to their local game store (damn snail-paced international mail). But the recent 'save my game' article from this month's Dungeon got me thinking a little about the Dungeon Delve book.
The Good - It is a slew of adventures that can be easily run in a night. As the Dungeon article pointed out, it's a great resource if you have to plan out a quick adventure. I'm more partial to using it as a quick encounter resource. Tag a few encounters in the book and use them if you need to make something up on the fly.
There is a lot of material here that could be applicable to every level campaign (or portions that could be regularly pilfered). I think this product is a good investment if just starting a low level campaign. Plus if you wanted to just make a quick one shot adventure for a nightly game (or a run to introduce new players), this would fit the bill nicely.
Additionally, this could be a good way to give players, and you as a DM, a snapshot of the paragon or epic tier. Just as a break from the regular campaign, tell players to roll up a lvl 25 character, sprinkle in a few magic items as equipment, pull out an appropriate delve, and have a run at it. This experience might help them rethink what feats and powers they'll pick up as they advance. Maybe after playing a certain paragon class for an encounter or two, they realize it doesn't quite fit their play style, and rethink the direction they'll focus on for future levels.
The Bad - Some of the encounters seem a little uninspired. There is a definite repetitive theme of a 3 encounter dungeon crawl. They do give some ideas for expanding delves. Straight out of the book however, I'd be more inclined to add a few more rooms and an encounter or two. Overall, I think many of the delves would need to be fleshed out a bit more before running them in a regular game.
Another big negative for me is the reliance on Dungeon Tiles. Yes, I get that WOTC is a business and they need to promote their products. But as the number of tile sets are so limited, overall I think many of the layouts are constrained. I'm certain this will be a trend that continues for other books. I'm hoping they release another 3-4 sets before coming out with another Dungeon Delve book. I'd warrant even completely remapping your own dungeon layout, and just drop the encounters into rooms of your own creation. As long as some of the major terrain features are there, I think it'll be just fine to plug and play encounters from the book.
The Verdict - Is this an indispensable D&D book to add to your collection? No. Could this serve as a useful tool for running your games? Sure. If your group is the meat and potatoes, dungeon crawling crowd, they'll likely love it. However, I think most of the delves will need some retrofitting to work with your typical group. If you have the cash, I'd consider it a reasonable buy to add to your library.