Went to Jordan Sept-Oct 2011. Had several guides. I felt this was the best as you feel you can actually use it as you go - that is to say ideal to dip into as you move from area to area.
Likes
divided into 8 or 9 sections by area - eg Dead Sea, Petra, Amman etc for ease of use
good photographs - I find the "pictureless guides" too dry
not overly verbose, decent size print, everything we tested was accurate
Dislikes
fractionally out of date due to recent strengthening of the JOD re prices
fractionally TOO thin
However this works - and the foldout map inside cover was frequently referred to throughout our stay.
ps didn't test drive the northern-most region of this guide