Since I just received my Erebus, and had a game tonight, I decided to see if my theory machine ideas would hold up in real games. I got a game against a 50 point Hexeris list, and I was facing 40+ infantry, including Swordsmen, Cataphract Cetrati, and Reivers (I was a bit puzzled at first, but having a ranged threat actually made sense). I was using my Terminus army, with Malice/Erebus instead of two Leviathans.
We had a Mexican standoff, with me having a slight charge range advantage (Overrun scenario), and Stealth to negate his shooting, which forced him forward. He couldn't advance to much without getting in Bile Thrall purge range, and one of his models got 0.1" to close to Erebus.
3 Focus, Puppet Master, Ravager, and an infantry army bunched up between terrain and in preparation of his assault the following turn... sixteen kills from Erebus. I was a sad puppy since I didn't feat and charge Terminus in range, but I wasn't expecting sixteen kills at all...
I know this won't happen every game, and Erebus has a terrible charge range, but a heavy jack version of Slaughterborn is godlike. I know Slaughterborn could have done the same, but with the incoming fire directed at Erebus, he would have been dead twice at the time.
I LOVE my new pet, almost as much as Terminus does. I guess Malice did fine as well, and cleared a lane for Terminus after the Bile Thralls had softened the Cetrari lines a bit, but he had his Harpoon shot of and had to do it by hand. My army suffers a wee bit from a lack of range, so I think I need to put Darragh Wrathe back in. The game ended with Hexeris failing the "do not get within 11" of Terminus" test, after half my army vanished during his feat round.