It's been years since I used the UG (I live here now, so no need to really plan anymore, I know my way around things) but I still highly recommend it! I thought it was an amazing tool and really helped maximize the time I spent in the parks, while giving honest and fair reviews. I recently came across the latest edition in a bookstore the other day, and noticed they've really added to it since I last used it, so it seems to me even better. A great investment, for sure.
TGM I've never used, so I can't advise you on that one way or the other.