I just received my copy of the guide in the mail, and it's absolutely incredible. It's professionally produced, mindbogglingly comprehensive, and has a crisp, clean layout. It's great for not just avid game collectors, but those of us who don't comb the thrift stores for rarities but who still want to read about them.
My favorite parts of the guide are the Santulli slants that offer opinions of the most memorable games, and the huge section devoted to the best game console ever made, the NES. My only gripes are that there aren't a lot of pictures to break up the text, except toward the back... and those snapshots tend to be a little pixelated.
Just one more thing... I'd like to offer a correction for one of the entries in case it hasn't been mentioned already. The hint listed for Super Mario Bros. 2 will only work with Super Mario Bros. 3. Maybe DP Guide 8 should replace it with information on how to use the potions and vase portals together to discover warp zones.