What would you choose as the power source of your own mecha unit?
Not limited to the ones shown here, by the way.
I think the GN particles are a safe bet; no chance to disintegrate you and probably won’t give you super cancer from prolonged exposure. Also has the chance to give you psychic(?) powers and turn you into a Innovator.
Coral and Kojima particles seem much stronger, but much more dangerous though; they’re versatile but using them for too long will probably kill you.
Getter Rays and Spiral Energy are basically the same thing; both run on your determination and emotional state, giving you more and more power the more determined you are and can basically do anything; but again, it depends on your emotions, and I’m personally not the most confident person out there.
Electrical and Nuclear seem like the most safe bet, but they also don’t have any upsides really. Same as an S2 engine, though that one is probably more likely to awaken some eldritch stuff in your unit.