An average (Imperial) psyker would get stomped, IMO. Most psykers either go insane or have abilities that are practically useless in combat. Even psykers like Eisenhorn, who are relatively low-tier, are far more powerful than an average psyker.
Now if you use an average Eldar psyker, sanctioned/primaris psyker, Space Marine Librarian, or Chaos Sorcerer, then it's likely a stomp in the other direction.