My copy was awaiting my return from the States. It is superb (OK, OK, I did the maps, so I'm biased) and is much more than just an update to the 1998 Aerofax (which I have), but includes a great deal of new information on the numerous variants of the KC-135, so the subtitle 'More Than a Tanker' is very apt.
Hopkins has flown many of these variants, including the 'real' spyplanes based on the KC-135 airframe. A great deal has changed in the world of the '135 since 1998, so if you have the original, I'd say this is more of a complete revision than an update: many new images, more details of operations and with more pages, a more comprehensive coverage of the subject.
Chris