First of all, every single one of the book's 240 pages is in full color and on very nice, glossy paper. I can't imagine why anyone would buy the paperback, which is in black and white and on average paper. The difference in price is only $7. Plus, the hardback contains the tweaked-for-TS GURPS Lite rules. The paperback doesn't.
The setting doesn't have any apocalyptic backgrounds or overtones. It's simply what the world might be like 97 years from now, extrapolating from technological trends. No alien contact, no Armageddon-type war, no nonsensical "scientific" breakthroughs that change the laws of physics. None of that. Just look at computing, robotics, nanotechnology, and genetic engineering, then imagine how they'll advance over the course of a century.
The setting isn't just another "let's buzz around the galaxy in spaceships shooting lasers at things". Instead, the author has taken very seriously a number of scientific books that are quite plausible in their predictions. For example:
Engines of Creation by K. Eric Drexler
Mining the Sky by John S. Lewis
Robot: Mere Machine to Transcendental Mind by Hans Moravec
The High Frontier by Gerard K. O'Neill
The Millennial Project by Marshall Savage
The Case for Mars by Robert Zubrin
Space travel is more in the background in this setting than in most other sci-fi settings. The big thing is how computers, nanotech, and genetic engineering have changed humanity and the very definition of humanity. Hence the title Transhuman Space. There is artificial intelligence, human minds uploaded into computers, physically-perfect genetically engineered humans, etc. There are a lot of philosophies detailing the different views of such things in the year 2100. And, best of all, the author doesn't make the asinine assumption that today's world religions will all simply vanish. Christianity, Buddhism, Islam, and all the rest are still around, and they aren't just little small fry, either.
In short, I can imagine that the world of 2100 will look something like the setting in Transhuman Space. I can't say that for any other sci-fi setting I've come across.