If you like psionics then this book is a good investment. The authors did a great job of updating the rules and bringing them on par with stuff from paizo.
Even GMs that prefer the classic Sword and Sorcery fantasy theme, can use the content to some extent. Abberations and other alien lifeforms that are "not from this world" can use psionic abilties and class levels to create unusual encounters or give seasoned players something new and challenging.
From changes made to the classes I would like to mention the Soulknife. This class in particular has seen a lot of improvement. Her weapon was made stronger and more versatile, while the many blade skills you can choose from give it unique options that are hard if not impossible to get by otherwise. I play one at the moment and neither outshine the others nor do I just stand behind and watch.
As others have mentioned already the artwork is the only big drawback. It is understandable though, as artwork can be a big cost factor for smaller companies.
Still, the pictures give you a basic idea how things look and at the end of the day that's what really matters.
