Q134 Are there any huge disadvantages to playing a Psitificer over an Artificer?
You have a smaller range of items you can make. Things like stat-boosting Wondrous Items and many utility items were not duplicated, and so a Psionic Artificer cannot make them RAW. Also, some of the more broken high-level spells have no psionic equivalent, so you can't make cheap scrolls. It's still a top-tier class, but has a little less flexibility. Especially when gestaled with Psion, as I know you're going to do. You don't need UPD, so why take a class that favours it?
EDIT: Also, there is only one Psionic Construct, the Psion-Slayer. No army of golems for the Psitificer.