Just ordered two Scavengers. I know they get a lot of heat on the various forums, and to be honest i think they're really expensive for what I get, except with Mortenebra. I probably can't get them in time for a play test, so I'll have to bring them to the qualifiers without any experience running them *gulp*.
The plan is to run them on the flanks, depending on where my opponent deploys his flanking solos, and then hopefully go to town on them. With Terminal Velocity they can assault 12.5" and if they kill their target they can retreat 7" afterward. This will either allow me to take out most solos and retreat to safety, or require my opposition to bunch up in the hopes of getting at my Scavengers with either free strikes or just making sure they're still in range after the Sprint move. This can be exploited by working the Scavengers as a team, or by keeping my Warwitches close by to spray the bunched up models.
The thing is, that even against an undamaged target the Scavenger under Terminal Velocity is rolling 3d6+7 to hit and 3d6+11 damage on a charge, which should take out most normal 5 health solos, and it's doing it without spending any Focus (will probably give it a Focus to make sure I can kill something and get away though, but that's what Warwitch Sirens are for, and they're running on the flanks anyway). If it's something a bit more resilient, I could always shoot it with my Harrower and if it's damaged the Scavenger is rolling 4d6+11 and will take out Dragoons if I give it a Focus to buy another attack.
I had planned for those 8 points to be used for a Leviathan, but after doing a lot of encounters in my head, I ended up with the annoying result, that the things I need to kill either have Stealth or really High DEF, which means that I'd have to dedicate 3+ Focus to a Leviathan in order to get that kill I need (assuming they don't have Stealth and just ignore me). With the Scavengers I can get that kill for no Focus at all, as long as I can get TV up, and I'm probably doing that every round anyway.