i use all of them and id say
Cyrax with the bomb timings, and string juggles into multiple bomb setups are the hardest.
and eveything you do depends on corent juggle location to where you are on the map, to make a read decision based on if you con connect their or not.. where you need them at that time, how you need to switch them up and where you want them to end, what ender you wan't, do you think they will block another, do you think if you cut it off and started another bomb ley they will backdash the setup and avoid the HTB, or do you think they will use that time to Armor, will you setup a bit. its all situational, and like another said its "on the fly" decisions to make depending where your at in relation to where they are floating or where they are eveading.
imo if you are in a combo by Cyrax, you made a mistake. all his shit is react-able and punishable.
CSZ with his simi input heavy 40% mid screens
Smoke with his side witches into last minute fade to escape out of bad inputs
Sektor last cuz he really only has 2 things F212 backdash and the normal teleport rc switch sides 21, 1112 , EX tracking, 111 armor corner stuff setup...
i had more lab time with Cyrax than i did CSZ.. and it seems its easier to open players up with CSZ than it is with any of the others, but its extremely hard to open up others who know the matchup with Cyrax, he has an overall weakness with neutral, and lack of meterless setups, and has no real safe way to open them up meterless, and obviously strings into net are super unsafe, and any real opponent will block that green flash and punish accordingly.