I have two copies of the book: the original hardback version and the re-released paperback from the 3rd edition. As someone has stated before the hardback leaves a lot to be desired. There are grammatical errors, typos, weak plot structure and some geographical problems.
However, the paperback is a different kettle of fish. The errors are (mostly) removed or corrected, the typos are gone, the plot structure has been tightened and the general editing is much improved.
For what it is (Action based FICTION) it is very good. You don't need to do too much thinking to keep up with the plot, it is fast paced and the action comes thick and fast.
My partner and some friends are ex-forces and although they chuckled at parts and said that some bits are way, WAY over the top they also said that a lot IS fact based and they enjoyed it. I hope this helps.