Doesn't seem like you can lose. The price is only $31.49 on Amazon, it is 1000+ pages, and Amazon (U.S.) gives free super saver shipping on it (since it's over $25 by itself). I presume Amazon UK does the same. So, if you like books ... go for it. (If you decide you don't like it, you could sell it to me for a discounted price.
The bummer would be we would have to account for shipping cost.) Of course, some people get along just fine with online documentation, forums, and google. I've got 3 of the Solaris 10 titles that come up under the OpenSolaris Bible in Amazon, but I just haven't had time to do much reading.