Been messing around with both costumes' movesets the last few days and there are definitely some differences.
Summary for people who don't like to read:
Cyborg has much faster up missle startup.
Cyborg has slightly faster straight missle startup and recovery.
Human has larger hitbox on the overhead in the 1,2,2 string.
Human's x-ray has lower projectile trajectory.
For people who like lots of details:
Up Missle - The difference in startup time is huge. Cyborg's is much faster. Wish I was able to do frame data because I'd love to see just how different it is. Recovery time seems to be the same between moves, though.
Straight Missle - The difference here is quite a bit smaller, but Cyborg seems to be slightly faster on both startup and recovery. Should also note that the Human fires his missle slightly lower, but not notably so. It's nothing like the difference between x-ray trajectories, and I honestly doubt it's enough to have an actual gameplay impact. Also, Human's missle appears slightly farther in front of him upon firing. I'm not sure if that's a pro or a con, especially if it comes with slower startup and recovery.
1,2,2 String - The final move in this string is an overhead that has a different animation depending on costume. Cyborg opens his chest plate and hits the opponent with a small, close-range explosion. Human holds his arm in front of his chest and does the same. For whatever reason, NRS gave the human animation either a larger hitbox or the hitbox is farther in front of Sektor because of his arm being there. In any case, this has two effects. One, human Sektor can be farther away from a croucher than the cyborg and still hit them (I think the added distance is about the size of Sektor's foot). And two, he can juggle with this string mid-combo at midscreen.
Honestly neither of these advantage are probably real impressive. The first two hits of the string have such small range that you'd never want to throw it out unless someone was crouch blocking right in front of you, so the increased range isn't really all that amazing. And the ability to use it in juggles isn't all that great either because midscreen there are better/equivalent options. Using the string in midscreen juggles will result in the overhead launching a juggled opponent across the screen. After the overhead you're pretty much limited to following up with either a straight missle, a teleport uppercut, or an x-ray. You can get a few hits in after a teleport, but the timing is damn tight, more so than after using F4,4 or F4,3 for example. 1,2,2 is cool in corner juggles (which can be done by both costumes) since it slows their fall, but midscreen it seems pretty meh since there are better/equivalent options with easier timing. Unless I'm missing something pretty cool, which is definitely possible. (Example midscreen combo - 1,2,B1 step forward 1,2,2~EXTU B2,1)
X-Ray - It's pretty common knowledge that the human has a lower projectile trajectory on his x-ray. This let's him squeeze in an extra hit or two on some longer x-ray combos the cyborg can't do for an extra 1 or 2%. Thing is, Sektor really only uses his x-ray to close out a match when he needs some unbreakable damage. Since the lower trajectory really only makes a difference in longer combos where gravity scaling really kicks in, this sort of defeats the purpose that most Sektor players use the x-ray for. Longer x-ray combo = more opportunities for your opponent to breaker before you activate the x-ray.
So yeah. Hopefully I'm not way off on any of that. Assuming it's right, I'd probably say the cyborg has a slight edge as faster missle startups are probably going to be more useful than the lower x-ray and bigger hitbox on 1,2,2's overhead.
Apologies if this is all already known.
...not excited for the scrubs who are going to pick him because of his retro though :/
