The idea of testing a unit each week is definitely interesting, but as I didn't feel in the mood for a proper game I started up a 10 planet map to get a feel for them. I stopped playing temporarily as the UNHANDLED ERROR spam due to the engineer-targeting bug, but here's my impression of them...
They are an interesting unit, but seem rather weak, and with so many blade-immune structures I was struggling to find a use for them. In my mind they're Z shredders that don't reproduce or vampires that hurt themselves instead of heal rather than a viable choice. I'd like to see them taking on guard posts and other structures that might be hidden under a forcefield, and perhaps doing some form of permanent damage as it leaves part of itself inside the structure. Maybe armour damage?
With an increase in strength it might be interesting to have the damage done to itself based on the the damage done to the target, so a core cutlass can cut through multiple mk.I microfighters but one-hit K.O.s itself against large targets.