I'm just going to copy and paste what I wrote in my FAQ:
Force Emission - some people swear by it when playing psi monk. I think it's garbage:
While the raw damage on paper could be significant, its damage is a new separate mechanical attack that's roll individually against enemies' mechanical resist/threshold which will usually vastly decrease its effective damage.
You can get as low as 4 action point per attack if you have high DEX. If you use Force Emission every hit it'll rapidly drains your psi points, leaving you unable to cast other psi abilities when you need them.
Garbage, even for psi monk, don't waste your slot. If you want to try planning a build around it w/ Force User and Telekinetic Proxy, create a new manual save file before the attempt, just in case you want to roll back your char.
I would love to be proven wrong on this one so I'll be very interested for any pro Force Emission argument/comment.