While I prefer USGS topo maps to my deLorme books, I carry the later in my car. They don't have the detail, and I have found a few errors, but nothing major (they misnamed the mountain my parent's live on, usually not a big deal). And it they are updated every years, unlike the quad maps which might get an update every 20 years in some places.
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-IronRaven
When a man dare not speak without malice for fear of giving insult, that is when truth starts to die. Truth is the truest freedom.