ill describe how my personal matchups go with the main key characters sektor players bump into often and if anyone wants my opinion on other characters ill let you know!
Sektor vs Raiden: 4/6 it could be lower if the sektor doesnt know how to fully use him, raiden can shun pretty much every move sektor has, if the raiden teleports correctly flamethrowers and rockets won't work on him. therefore if the sektor player only knows how to zone he's in trouble. sektors best bet is to try and use some up close frame/rocket traps to bait a teleport. even then sektor cant do anything about the teleport as he cant jab on reaction if the raiden player down 4's him, that said if the raiden player jumps or goes for a string sektor can easily uppercut it. if a raiden is desperately trying to teleport everything up close this is where the frame traps come in to play as he wont be able to and you will probably get a nice damaging combo to punish him for it.
Sektor vs Kung lao: 4/6 i use to think kung lao was a horrendous matchup for sektor untill i fully learned the matchup (apart from that teleporting tactic sim was doing at svb haha) for the most part sektor can punish pretty much all of kung laos attacks, if he spins off the bat a 1,2,<1 will punish giving you a 47% or if he does a few jabs THEN spin his 2,1 will punish giving you a slightly less but still decent punish combo. you can beat all of kung laos teleport options with an uppercut apart from the regular kick that can be comboed into, with that you need to wait for the kick to come out THEN uppercut. or if you want to play it safe you can just safe duck or down 1. his dive kick and teleport is easy to bait mainly because kung lao will usually try to do those to beat your projectiles which brings me to why i think it's a bad matchup. He's almost impossible to zone which is sektors primary function so when you take that out of the equation you're left with your own bag of tricks such as frame traps, upward rockets or leg lift fainting. once kung lao is in sektors face it's extremely difficult to get him away unless you do a wakeup ex teleport which is safe on block, this is a get out of the corner free card almost because even if they block you can still jump back giving you another whole area of screen to work with. however being able to be hit out of the teleport on startup hurts him especially against kung lao or cage.
Sektor vs Jonny Cage: 5/5 i would put lower against sektor if i was going to judge this by how matches between me and foxygrampa go because he's played my sektor for so long now he knows how to deal with him like the back of his hand but this is for the mostpart. when the second the round starts its good for sektor as he can poke at him or zone him comfortabley, but the second sektor is near or in the corner the match is entirely in cage's favour. sektors options are limited and a good cage player can easily keep sektor in the corner. if a cage is greedy and wants to attack you on wakeup you CAN wakeup ex teleport giving you a decent 41% corner combo which ends in rocket pressure (i will be doing an in depth video tutorial to show all of this) but for the most part a good cage is relentless in pressure so having full screen coverage is a luxury that is rarely given. In short its just as hard to cage to get in as it is for me to keep cage away so thats why i think the matchup is even.
Sektor vs Sub zero: 7/3 i have faced many many decent sub zeros since release and pretty much all of them have ended up as a comfortable win on my part, This isn't because the sub zero player is trash it's because sektor can hurt sub zero from a distance but sub zero can't, if you have the life lead sub zero must come to you to do damage and even if a sub zero goes for the ice ball trade from distance i can see this coming and teleport on reaction due to how slow the iceball is. if a sub zero knows how to do the ice claw cancel tactic once im frozen it can greatly benefit him because he can then play more aggresive which could perhaps turn the matchup into a 6/4 due to sektor not having much wakeup options but even then the ex wakeup teleport is lethal against sub zero because his normals are quite slow compared to other characters. if a sub zero is slide happy then its just an easy win for me, especially if you trap them with rockets up close. you can block the slide and then go in when the rocket connects.
Sektor vs Cyrax: 5/5 mustard has already explained this above
Sektor vs liu kang: 6/4 pretty much all of liu kangs strings once blocked can be shunned with a down 1 so the kang cant do anything else which will always give you a free jump in or jump back, you can zone him extremely easy because even if you trade from distance he gets knocked down which can let you rocket him before he fireballs you, needless to say ex or not liu kangs charge attacks can be easily baited and blocked. his kick can be punished with a full 1,2,<1 and his bicycle kick can be punished with a <3,4. if the kang is greedy wakeup teleport wins again and especially if the kang has you in the corner, even if he blocks your ex teleport you can get away from him anyway it doesnt even matter if he knows you're going to do it. if you have HIM in the corner he has no good wakeups that will stop you from doing rocket pressure, you can block pretty much whatever he throws at you. that said i think it's 6/4 because sektor MUST be on point with his blocking otherwise the kang will run rings round him seeing as his basic combo takes you into the corner pretty much every time.
if you want to know about any other matchups ill be glad to give my thoughts
i'll also be doing a written guide soon and a very in depth video tutorial, stay tuned!