Legends of the Psions is a great resource for players looking for some fun new options at the table. One of the biggest selling points is the new Psion class. The Psion of Creed's Codex is a martial character, with abilities inspired by Jedi and other "psychic soldier" type characters, and plenty of opportunity to customize to fit one's playstyle.
Also included in the book is the new Exochron race, who will give players different bonuses depending on what class they take (almost like a favoured class bonus from Pathfinder, although it is mechanically different).
Feat Paths are also a new feature of the book. These are chains of feats (one feat acts as a prerequisite to the next) that almost act like a second archetype for your character.
If you're on the DM-side of the screen, there's monster stat-blocks with a lot of lore behind them that can help to flesh out Psions in your world.
Creed's Codex also keeps up a high quality of artwork, which was appreciated about Arcane Secrets. Overall, I am very pleased to give this book a place on my gaming shelf.