Okay I recently completed a game with Cutlasses. Unfortunately, it wasn't the actual game of the week. The GOTW save file was made during v4.046 and had parasites enabled, which unfortunately made it unplayable for several days. To keep with the spirit of the Challenge however, I played a similar game (albeit on a harder difficulty), and started with Cutlasses as my bonus unit.
Cutlasses:
Cutlasses are a neat concept, but I wouldn't give them much more credit than that. Being surprisingly expensive for a unit who's role is to basically commit suicide, their damage is surprisingly lacking, and they die extremely quickly. The dichotomy of "suicide" units in RTS games is that they have to be extremely good at what they do, otherwise the player will simply avoid using them and build a unit that can fill its role better without killing itself in the process. The baneling of Starcraft 2 is a good example of a worthy "suicide" type unit. It is a melee range mobile bomb that, if microed correctly, can take out entire groups of enemy units by itself. It is quite fragile, and somewhat expensive, but if used correctly can be absolutely devastating to enemies. Cutlasses seem to have the opposite effect. Even if microed correctly against their bonuses, they still seem to do way too little damage to be worth the trouble or Knowledge to try and upgrade them. They have no aoe damage (something very strange for a "suicide" unit in an RTS game), and most units can fill their role better. I see no reason to build these.
Luckily during the course of my campaign, I was able to test the etherjet extensively as well.
Etherjet:
The etherjet is an interesting idea for sure. A cloaked fighter like unit that can drag its prey across the planet into waiting enemies. The problem is, it doesn't seem to come in useful that often. It is very weak, having only a fraction of the health of fighters, which are already considered fairly expendable units. Basically, they die as soon as they are breathed on. I suggest giving them significantly more health and perhaps taking away their cloaking ability. This doesn't seem necessary for the role they are intended to fill, and the AI will probably see them anyway, definitely when they start dragging things. They aren't up to par but they certainly show a lot more promise than cutlasses, for what it's worth.