Most powerful versions? I'm guessing that's new-52 Cyborg and pre-52 Steel, if I'm not mistaken.
Assuming this is a random encounter, I'd give it to Cyborg after a tough fight. Steel is pretty powerful, particularly his hammer. The hammer can absorb kinetic energy to make it stronger, and the thing was powerful enough to alter the trajectory of an airplane. But Cyborg's promethium armor should be able to tank hits, and with morals-on I don't see Steel going to full-power. Steel's one advantage would be the durability of his armor though - even a bite from General Eiling didn't crush the armor to the point that Steel's human hand was injured.
But Cyborg has more firepower - with energy machine-guns and the white-noise cannon. Added to that would be Cyborg's ability to assimilate Steel's tech, and I think his technopathy abilities are greater than Steel's armor. He'd be able to search for intel on Steel, and since he doesn't sleep - Cyborg is also constantly upgrading himself. There's also the matter of flight, which I'm pretty sure nu-52 Cyborg has. And if worse comes to worse, Cyborg can still BFR Steel, too, with his portals.
I suppose one could make the argument that Steel has constantly shown ingenuity as an engineer, and that he arguably has more experience than the rookie Cyborg. There is the possibility he could outhink Victor, but I think Victor's superior power should grant him a hard-fought win.
Though personally, I much prefer Steel as a character :P
Kid Flash had to die because he was a main character in the show.Superman was still on Rimbor but if they wanted to save kid Jay and Captain Marvel(with speed of Mercury) could have took some of the energy blast. Of course this was young justice not captain marvel or original flash show.
Great episode love the way the adult members came out first then the younger ones back them up. Reminds me of the first season great episode before the finale and then even better finale. Too bad its a series finale and not a season finale.