I am sure I am not alone when I say, that I, along with other noobies, would very much appreciate a guide to building a Psion (choosing the right powers and feats).
I seem to find only a guide describing 3.5 Psionics, but given how much has changed, I would be overcome with happiness were someone with great deal of experience to write a new definitive guide to Psion.
What I would like in especial is colour-coded power selection (a sort of "must have)" for each discipline.
Here is what I've found (and use) so far:
3.5 Psion guide:
http://brilliantgameologists.com/boards/index.php?topic=10238.0
XPH to PF conversion document:
http://www.giantitp.com/forums/showthread.php?182797-Pathfinder-Psionics-vs -XPH-Psionics-A-Handbook
And finally a PF Shaper guide:
http://www.giantitp.com/forums/showthread.php?232673-Shaper-Astral-Construc t-CharOp-Guide-Pathfinder
I don't believe that that much has changed. Some powers got tweaked, as well as classes. But really, most were "buffed" and more options given. PFRPG promotes single class progression, instead of multiclassing out.
The basics of the guides are still useful, you would just have to check the powers you choose (most of which would still function as they did) that would have been save or die/suck/lose and metamorphosis/transmutation type, because those were the types most likely to be redone. The theory behind builds is still the same.