Re: CthulhuTech?
Having played CoC and Cthulhu Now, the impression I got was that the tech was irrelevant to the adversaries you fought. Modern weapons make a bigger boom, but the monsters are still scary. Space Horror is a subgenre where even with shiny toys, there are still things out there which can kill you (or worse). I refer to movies such as the Aliens series, Starship Troopers or even (shudder) Jason X. I think a CthulhuTech campaign could work with mecha. Hitting a Great Old One with a railgun would hurt/annoy it, but that's about it.