To be fair, however, I think that Screamerstar is going to keep an alternate mode where the Heralds hang back with Horrors squads until some of bolts are spent, giving you only one Psyker per squad to hi. I certainly wouldn't set up all 4 in one unit if facing Sororitas. It will certainly hurt Screamerstar as its usual Deathstar configuration won't be effective until the bolts are spent, but it's not as if Heralds, Horrors, and Screamers are bad units on their own. If you need to upgrade first to a Veteran sergeant in each squad in order to take that Condemnor boltgun, for 6 shots you're spending about 120 or so points, which hit 4 times and kill 2 Heralds (plus 4 Horrors if they're holed up in Horror squads). That's solid given that each Herald is around 130 pts, but it's not an Auto-Win button.