I whole-heartedly agree with a lot of its advice. It has an entire section on choosing tripping companions. I find that tripping with somebody can either create or enhance intimacy-- not necessarily sexually, but tripping makes you emotionally vulnerable, so choose companions that you are at least comfortable with and feel friendly towards.
They corroborated the point I made here about citrus fruit!
They also have coined (as far as I know) the term "triptoys," which is going to become an indispensable part of my vocabulary. However, Jell-O is a really bad idea. My favorites include glow sticks and other lighting stuff.
I disagree with some of it, though, too. It recommends not going outside during your first trip, which is just insanity. Obviously, avoid busy parks and public places during your trip, and make sure you can find your way back to home base, but if you have an empty backyard or something at your disposal, rock on!
Their advice on trippy music is entirely wrong, unless you share their goal of an enlightening sort of trip (which is a very noble goal, but not one that most people share). Trippy music that I like when I'm sober (Black Moth Super Rainbow comes to mind) is just way too much when I'm tripping, and I'm not suddenly going to start liking drum music just because I'm inebriated. I recommend music that you usually like that isn't too abrasive.
Other than those two flaws, it's a great guide. If you haven't tripped before, you should read it (in addition to my advice) to prepare yourself a little bit and then TRIP. DO IT. :)